Car Heaters

A car heater is a device used to heat the engine of a car, especially during cold weather. Commonly used in the northern US states, Canada or Scandinavia, the device warms up the car’s body and system for easier starting.

2,329 Questions
Car Starting Problems
Car Stalling Problems
Car Heaters

Is it necessary to warm up your car in the morning?

It is necessary on cold, especial extremely cold days. REASON BEING: Is that it takes the oil to reach it's proper viscosity longer time than on warm days. When you do start car, don't race it or you'll be doing more damage. Let it stay at idle for about 3 - 5 minuets until you see the temperature gauge start to get to move to a hotter position, or better yet, until you have heat. Reason is that thick oil cannot easily flow though tiny holes in crankshaft, push rods not getting oil into small spacers in cylinder block, valve guides, rocker arms and oil control rings leaving a dry cylinder wall, which causing wear to cylinder bore. Sometimes in really cold places, they suggest using a lighter gauge oil.

I will give my answer which is in opposition the the above answer somewhat. In years past when cars had carburetors it was a necessity to warm the engine up before driving off because the engine simply would not run correctly until the carb got warm. Today it is a bad idea to let the car idle for more than a couple of minutes max before driving off. Reason being is that on todays modern engines with computer controlled fuel management systems it is not necessary and is in fact a waste of fuel and pollutes the atmosphere plus harms the converter. Modern fuel injection systems do not need to warm up to work properly as an old carburetor did. They work instantly and the ECU adjusts the fuel/air mixture to compensate. Modern oils of today are also a far cry from what they were decades ago. Modern Oil sticks to all parts better today than in the past. This is not the same formulation that we had decades ago. There is a thin layer of oil on all parts when you start the engine due to modern refinery processes, so you are not causing wear to that engine if you drive slowly until it reaches full operating temperatures. Modern vehicles will warm up very quickly if driven but not so fast if sitting at idle. You are also doing your catalytic converter no good by letting this very rich mixture of fuel/air enter a cold converter that does not work well when cold. Just drive away slowly, avoiding full throttle until the engine is warmed up. This is 2010 not 1955. Things have changed.I can see the above point of view. But there is still a disagreement on oil. yes there will be a very, very thin layer of oil on the cylinder walls, but even sythetic oil will settle downwards ,and on a 20 degree day will be sticky and wipe off in one piston stroke. it still ,in my opinion, takes a little bit of time for oil to thin out as it gets warm. Has enyone ever went to change oil on a 10 to 20 degree day. It barley comes out of the drain hole, unless you let it run for even a minute, can you picture this oil flowing through tiny openings. however, point is well made that idleing and driven slow for the same amount of time will do the same exact thing. Main point is ; don't reve the engine right away, or drive fast for a few miniutes. Note: in places like Alaska, they use a heating source overnight because the car may not even turn over or do it slowly, because the oil is so thick.

Ans 3 -The second answer is the correct one. Letting a modern engine idle for long periods is not good with modern oils being as 'clingy' as they are.

Chevy Blazer
Heater Cores and Blower Fans
Car Heaters

Why would a truck heater only blow cold air?

The heater core is blocked, or a heater hose has collapsed, keeping hot engine coolant from getting to the core. The "blend air" door may be stuck in the open position, keeping warm air from circulating, and dumping in cold outside air. I am assuming that engine coolant and water pump is good.

Heating AC and Engine Cooling
Air Conditioning and Coolant
Car Heaters
Air Compressors

How do you repair the Heater Air Conditioner switch?

go to the salvage yard and put that one in and it will work. It's not hard to get out just two wires you unplug. Make sure you take off the neg from you battery before you install the one you got.

Try replaceing the a/c relay. On my Chevy S-10 blazer the relay is on the firewall passenger side.

Your blower motor is failing and is only working on high speed.

Heating AC and Engine Cooling
Heater Cores and Blower Fans
Car Heaters

Why would your car heater overheat?

I have a 1992 Plymouth Sundance with 130000 miles. 4 cyl, 2.0L It has been well taken care of with regular maintenance between 3k to 5k intervals since I bought it with 58k. The car instantly overheats when turned on. The heat blows frigidly cold air. It has a thermostat that is ~5 months old. The car will shudder and shake and then cut out when left idling or when it over heats. It is not losing coolant, but the car smells like burning antifreeze when you lift the hood. It will also steam and or smoke that escapes from under the hood when you turn it on. 1.) What are the possible diagnoses? 2.) How much will it cost? (Chicago area) 3.) Is it worth spending the money on a rebuilt car that I've had since high school, or should I just give up and buy a newer car? The most common cause of simultaneous engine overheating and no heat from the heater is extremely low engine coolant level, in other words a large pocket of air in the system. In some cars it's fairly easy to get the air out, in others it's very tricky. If there's a leak causing coolant loss, that will also have to be addressed or the problem will recur/worsen. Check 1. Your Thermostat (70%) of the time it is your thermostat. 2. Check and see if your radiator is clogged (Also very common).

Another issue is if your car overheats during idle, then it could be the electric radiator fan.

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Car Shaking Problems
Ford Explorer XLS
Car Heaters

What causes a car to shake when stopped at lights?

You might have a problem with you idle control motor (or servo kit). This is part of the fuel induction system. Turn on the air conditioner while in park, if your car shakes (more than normal) that might be the problem. You may have to spend $200 on a new idle control motor or might simply have to adjust a few screws that regulate air intake. Check out a repair manual for your specific model of car so you can troubleshoot yourself and save money, but be carefull because fuel systems can be dangerous to work with so follow all safety precautions!I know it's broken motor mounts that caused my 1989 Buick Skylark to shake while idling at stop lights. The vibration was a little less when I put the car in neutral (I think it idles a little faster in neutral and the vibration lessens) and it's a lot less noisy when I take the crap out of the glove box. :)

It happened to my Mazda/98, After i changed the engine mount, No more shaking.

I had bad shaking when idling in park or at a stop light. I replaced the timing belt and got the cams retimed. After that it was good.

Antifreeze and Engine Coolant
Heater Cores and Blower Fans
Car Heaters

Why would the car heater not blow warm air?

First check the water level. If the water level is low or very low, you may have air in the radiator. If you have a small leak, you will have enough water to cool the engine but not enough to heat the heater core. Adding water to the radiator may not be enough. Air in the heater core equals no hot air in the cabin. This problem is so bad in some engine configurations that some cars go as far as to actually have a 'bleeder' at the front of the engine, by the upper radiator hose/thermostat housing (Dodge, BMW, etc.). The heat selector lever/ switch in the cabin may be defective (electrical) and may not open the hot water valve enough, or even be disconnected (mechanical). Some (Ford and foreign cars) use vacuum to operate the valve and those lines may be cracked, worn, pinched or just leaking. You could also have a clogged heater core. These are 3 possible items you could start with, in that order. The thermostat could be at fault, but this is a give away. If the thermostat is stuck open or missing and you drive the car for a distance, the engine will take a while to warm up then overheat, and the cabin heat will follow the engine temperature. If the engine overheats, you need to take care of that motor more than worry about the heat in the cabin. As you said, you're not asking what to do with your overheating car. You would have taken care of that motor by now and taken care of your heater problem with it.

Antifreeze and Engine Coolant
Heater Cores and Blower Fans
Car Heaters

Why would a car heater stop working and just blow cold air?

There are several reasons for your heater to blow cold air, the heater belnd door being stuck, no thermostat, low coolant, diagnosis is key.

If you have a 3.1 V6, you may need to bleed the coolant system. In front of the engine passenger side, you have a bleeder screw, with the engine off, surge tank cap off, open the valve until coolant flows smoothly, close the valve, check coolant, add if needed.

it's a $5.00 thermastat The problem could also be low coolant level. If the coolant gets too low it will not pass through the heater core and therefore will not heat the cabin air.

You may need to have your heater box inspected. It is possible for the flapper to be jammed or broken. It is a big fix so make sure to check coolant levels and leaks as well.

Car Heaters
Heating Ventilating and Air Conditioning

What could be wrong if your central air conditioner blows cool but not cold air and seems to be always running?

  • Your condenser may be dirty and the evaporator coils should be cleaned there may be inadequate air flow around the condenser. if there is a leak, your unit may be out of refrigerant you might have a leak in your duct system[From The Home Energy Saver a webpage from the Berkeley Lab website.]
  • You could have the same issue we have in our home currently. For some reason, the inside unit will run and run and it will get extremely hot in the house. Called out our service guy and the first thing he had found was that we had tripped the breaker for the outside unit (condenser I believe). Go with the cheap easy stuff first....
  • I had the same problem and when the service tech came out it was determined that a faulty relay was to blame - the ac and heat were on at the same time! Hope this helps.
  • Freon too low
  • This answer is more often incorrect than not. Most new modern A/C units have a built in safety device to disable the compressor if the Freon is too low.
  • Their could be a few answers to your problem. The condenser [ outside coil ] could be clogged causing a higher pressure witch means higher temp. it could be as easy as taking your garden hose and washing the coil, if the is packed you may need a power washer to clean the coil. You could also be low on refrigerant (Freon), which means you have a leak which needs to be repaired before you add refrigerant. Leak checking and adding Freon has to be done by a certified tech. You could wash the coil your self. Make sure the unit is off by the breaker to be safe.
  • Never clean coils with power washer you will regret it condenser coil dirty evaporator coil dirty low on charge freezing up most of the time indoor coil the evaporator is not cleaned by service techs causing coil to freeze or being over charged clean is the key all coils not just the outside.
  • We have had this happen to us twice now. My husband's uncle works in HVAC and suggested that the first things we do were A) check the cleanliness of the filter and B) turn OFF the air conditioner (I think he also suggested tripping the fuse for the unit) for about 10 minutes. Luckily, both times this has happened to us, this has fixed the problem. I don't know what causes it to stop cooling the air sufficiently but turning it off seemed to reset it somehow. I know this is not a true "fix" but it is a good first step before calling a repair man.
Heating AC and Engine Cooling
Air Conditioning and Coolant
Car Heaters
Heating Ventilating and Air Conditioning

Why would an auto AC turn on but only blow warm air?

Here are responses: * Several things could be the cause. Low coolant. Heater valve. The belt. The compressor. Check these in the order shown. * You most likely to need a new temperature control switch in your heater/ac. This is the switch in the dash; easy to change.

Cars & Vehicles
Heating AC and Engine Cooling
Chevy Blazer
Car Heaters

Why would a car only overheat when driving on highway not when driving around town?

Each of these things can be checked independently of the others without spending any money on parts.

1-Low coolant level.

2-Restricted airflow to the radiator as from leaves or plastic bags in fron of it, or the plastic under-skirting being broken away (as from running up onto curb-stops.)

3-Restricted flow of within the radiator or hoses. Restricted flow in hoses is rarer, but rev the engine to 2000 to 2500 RPM for several seconds after the engine is fully warmed and look for either radiator hose to collapse. To check for restricted radiator, you can take the temperature of the radiator with a non-contact thermometer in several places or you can open the cap (if so equipped) and look for white deposits. White deposits mean you need a radiator. If your radiator has no cap, remove the upper hose and look in through that opening.

4-Poor heat transfer. Poor heat transfer can be radiator to air (look for missing or greenish radiator fins) or internal due to a high ratio of anti-freeze to water (use a hydrometer) or internal due to scale deposits (with an iron engine your coolant will be brownish, aluminum engines can be checked by removing the thermostat or water pump and looking inside for whitish deposits).

5-Insufficient coolant pumping. Metal water pump impellers can erode over time, especially with excessively old coolant. Plastic water pump impellers can break randomly, and are prone to break if the engine is a Ford Duratec or Volkswagen or if the water pump hasn't been replaced after an overheat. Cheap substandard $5 replacement water pumps have often have a poorly designed impeller that can become dislodged. To check, remove the thermostat(s) and fill the system with coolant or water. Remove the radiator cap (if so equipped, otherwise surge tank cap) and observe the coolant level while rapidly snapping the throttle from closed to wide open. The coolant level should change drastically (more than 1/4 inch) if the pump is good.

6-Exhaust gases leaking into radiator. This is usually caused by a leaky head gasket, but can also be caused by a cracked or eroded engine. Note that GM Quad-4 engines are particularly prone to cracking, and four cylinder Chrysler engines and cars owned by youthful males or Jewish women are prone to head gasket leakage. An electroneic gas analyzer can be used to check this condition, but for the do-it-yourselfer, check with the local parts store or tool dealer for a disposable chemical based detection kit.

7-Boiling. Boiling can be caused by too much water in the coolant, insufficient pressure due to a leak or a bad cap, Partially restricted water jackets, or overheating due to another cause. Presumably, any other overheating has already been ruled out so you might as well check for leaks, then replace the coolant with a correct mix and put a new cap on it. If you have a restricted water jacket, you're going to need the engine rebuilt.

***Fan related problems will _not_ cause overheating at highway speed.***

AnswerThere are many possibilities. But if you are traveling locally a very short distance, possibly the engine does not reach temperature to open the thermostat. The water is circulating in the engine. On the highway, the car may reach temperature, opening the thermostat. Now the water is also going through the upper and lower radiator hoses and radiator. If there is a small leak in the hoses or radiator, that would cause overheating, now that the water is leaving the engine, (and is under pressure).

A pressure test of the cooling system usually will show a leak.

Especially if you notice fluid under the car after driving.

AnswerA weak lower radiator hose could collapse at highway speeds but not lesser speeds around town. AnswerThe most likely cause is a plugged radiator. Over time sediment build up in a radiator. Every time a radiator is heated and then cools the sediment collects at the bottom of the radiator slowing reducing it's efficiency. I have seen this particular overheating problem numerous times and traced it to a plugged radiator. Take it to a shop and have the radiator rodded and repaired and it will cure your problem. AnswerHave your clutch fan checked. the tension of the clutch can weaken causing the fan to turn too slow at higher rpm's. AnswerI had a similar problem. If the car has sit for any length of time a mouse or rat may have built a nest in the muffler or exhaust pipe. This causes back pressure to build up at highway speeds but not at short low speed in town driving. If one of the other ans did not fix the problem this is worth a shot. Answeranother possibility is a blown or leaking head gasket. A cracked head/block will also cause a vehicle to overheat when operated at higher rpm, the crack doesn't expand until temperature is excessive. typically the vehicle will produce a smoky emission from the exhaust, but it is actually steam from the antifreeze/water mixture leaking into the combustion chamber.
Cars & Vehicles
Asian Cars
Car Heaters

Why is car sluggish in the heat?

i imagine that the car itself is in good working order so to that effect the computer may be pulling timing to avoid detonation based on the inlet air temperature.

Car Smells
1995-1999 Dodge & Plymouth Neons
Car Heaters

Why would you smell fuel when you turn on the heater?

May be separate problems. A small fuel leak in the engine may be the source of the 2 scents. A coolant leak may be the source of the poor heat and burning smell. Get it checked out before you have a serious problem. Next time you run the car, shut it off, lift the hood and try to smell where the source of raw fuel is, or any rising smoke.

Heater Cores and Blower Fans
Jeep Grand Cherokee Limited
Car Heaters
Chevy Trailblazer

How do you repair a 2002 Jeep Grand Cherokee dual climate control that blows cold on on one side and hot air on the other when the heater is running?

There are several things that can cause this problem with Jeep Grand Cherokees. The actuator (door motor) can cause this, the door could also be broken. There is an good article that goes into more detail - the link is at the bottom of this page. Often, the actuator motors are too strong for the plastic doors, and they break over time. The typical fix involves removing the entire dash and replacing the plenum assembly. There is a DIY kit by heatertreater that provides instructions on how to perform the repair without removing the dash.

I just started experiencing this same exact issue with my 2002 Jeep Grand Cherokee Limited on a road trip yesterday! It works as it should on the driver's side, but only blows cold air on the passenger side regardless of what temperature you set it on! Also, even if I completely close the passenger vents, some cold air still comes out from them and also from the floor area!

I had the same problem! Here is my cheap quick fix. Remove the glove box lid, there are 2 rubber retainers that hold it in place, just pull them out they are easy to put back, the lid will now drop down to reveal the the door motor housing, disconnect the electrical lead(Make sure you remove the neg lead on the battery first)Undo the 2 screws and then pull out the motor. A new motor cost me approx 100 pounds. If you do take my approach make sure you test the motor before you buy new as it could be some other problem. Once you have removed the motor it's easy to open and close the door by it's spigot, just to make sure it's not stuck in any way. My final test was to check for power to the electrical lead. Reconnect the battery. While turning the temp conrol check with a meter to see if there is power to the lead.

It sounds like you have aq problem with the right temperature door assembly. I have a similar problem with my 1999 Grand Cherokee Limited, but, in my case, the unit just blows cold air. The question is: How do you access these door assemblies to change them? Help! I am a do-it-yourself person and want to know where I can locate information about how to access the AZC system door assemblies to change them? I understand it involves removing the entire dash board in order to get access to the passenger side one that is broken. To do so I need some type of repair manual.

All I know is I have the EXACT same problem with by 99 jeep grand Cherokee. It started with one side blowing cold and the other blowing hot. Now, both blow only cold air. I took it to the dealer and they wanted to charge me $800 to fix it stating it was some switch that has been going out in all jeeps this model with dual heating system yet they would not consider it under warranty as a issue. Hence, I still have no heat.

I just had the problem on my 01' jeep grand the dealer told me it was a bad bun door and actuator on the passenger side at a charge of $1200.00. If your good with cars you can do the job yourself and I mean good this job was a pain in the butt the dealer est. 12hrs (plus u need to disc. the heater core and evap. for the ac) of their time it took me exactly that. Once I got the HVAC system out of the truck I noticed since the car is temp. control zoned the passenger Sid bun door which controls the flow of heat to the passenger vents was broke. The dealer was aware of the problem picked up a new part for $200 and slapped it back together worked fine( the actuator was not bad it just doesnt respond to a broken door so don't let them sell you one, you should only need a new bun door)


The problem is a wear out mechanism with the blend doors. The doors break and are stuck in the AC position...NO HEAT. There is a new product that solves the problem. Search on Google for "heatertreater" for a complete explanation of the problem and a solution.

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The problem with the system is the design of the actuators. The failure of this so called" bun" door is due to the poor design of these actuators. Over torque and excessive wear leads to failure....The only way to resolve this problem is by replacing both actuators and the temperature blend door assembly. Do not just replace the door!!!! ( note: fresh air door has same problem) I average one grand Cherokee a week in my Cooling systems repair shop. 675.00 is my going rate. It pays 6.1 hours and nothing more...don't be robbed by the dealership and stay away from driveway mechanics. Beware that your entire instrument panel must be removed along with the evacuation of the refridgerant. Not a "do-it-yourself" deal! Good luck and never by a Jeep again!

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Your failure description is the classic fail description for broken blend doors, and this is a common problem on the GC. There is an inexpensive DIY kit on Ebay from heater treater that will fix the problems without having to remove the dash panel.

The HVAC system is computer controlled and when the doors break, the computer senses that the movement of the doors is out of spec and shuts the motor down. Actually it is rare for the actuator motor itself to go bad. Usually it's a broken door combined with computer control. You can check the motor with a 9V battery and a snap connector. Just touch the wires to the motor terminals and check that it turns.

Another Example

I just thought that I'd add my experience: I have a 1999 Jeep Grand Cherokee Limited 6-Cyl. About a year ago heat went out on passenger side (cold air came out on passenger side when heat was on and coming out on driver's side). Spring and Summer came, so I forgot about it. This Fall (maybe 1-2 months ago) I was reminded of the problem when the cold air came back. Now, about 1-2 weeks ago, all blower functionality is gone ... a real problem if you need to defrost the windows! I'm going to try the AZC test and look into the HeaterTreater. I'd hate to put any more big money into this vehicle as it has been a true money pit. I'll never buy another Jeep. It's a classy ride, but I've put more money into repairs for this vehicle than any other two vehicles I've owned.

Easy fix is available

There is a video available that shows the complete repair process and goes into an explanation of the root cause of the problem and the solution. You can also find the video by searching on YouTube. This is a very common problem on the Grand Cherokee and the kit gives a simple effective fix for the problem and is much much cheaper than taking it to the dealer.

Assuming you are going to replace the 99/04 Jeep Grand Cherokee blend doors yourself.

You would start by disconnecting the negative battery cable.

If you are going to remove the dashboard, etc to replace the blend doors.

some websites give you complete instructions with plenty of pictures.

It will take the average person with little or no auto repair skills approximately 12 to 16 hrs.

The vehicle will have to be taken to a shop that can recover the refrigerant before you start removing the dashboard and HVAC box..

If you are going to do the type of repair where you cut an access hole in the side of the HVAC box.

A short version of how the access hole repair is done.

Disconnect the Negative battery cable.

Lower the glove box

Remove the actuator motor - You will need a Phillips screw driver

Cut an access hole in the plastic HVAC box - Use a multi-purpose cutting bit, you will need a rotary type of cutting tool, like a Dremel, RotoZip, etc. Or you could do the cutting by hand with any type of small cutting tool, it will just take longer doing it by hand. Or some people have used a narrow pointed soldering iron!

Remove the broken blend doors

Install the new Blen Dor dual control blend doors.

Replace the actuator motor.

Close the access hole - Replace the wall piece of plastic you cutout -Use foam tape or an aluminum tape to cover the groove made by cutting the wall.

Close the glove box.

It is almost as easy as what you just read, the hardest and the most time consuming thing to do is cut the access hole.

The job should take between 30 minutes to 1 ½ hours. Depending on how long it takes you to gather your tools, etc.

Before you do anything major find you hvac fuse, pull it, then put it back. It might be in the fuse box under the hood or the one inside. All mine needs is to cut the power to the havc unit then it resets.

Chevy Blazer
Heater Cores and Blower Fans
Car Heaters

How do you replace the heater core in a 1996 Chevrolet Blazer?

Ok you have to remove your all the parts of your dash. When this step is done, you gonna see a plastic black box, remove this one (3 Screws). Under this one you can see your heater core.

When this step is properly do, open your hood. Look on your firewall (Up Passenger Side) and remove all bolts, remove the 2 heater hoses. Remove your heatercore and replace it, Redo all of this step inverse for reinstallation! Good luck!

(Sorry my english, im not the best in this language!)

But before you replace it...

If you think it may only be clogged, turn heater controls to full open/hot. Then turn off engine. Disconnect heater hoses under the hood. Connect a short hose to the "input port" to carry dirty water away from your engine. Connect another hose to the "output port." Shoot water from a hose-end sprayer into the "output" to backflush the core. My heater in 98 Blazer had quit heating. I just had to wash the crud out it it worked fine afterward. (it was going to be a BIG job to take off enough dash parts to get to the core to deal with it)

Heater Cores and Blower Fans
Car Heaters

Why does heater work only when your car is idle?

I am going to assume that you are pondering why the heater only maintains heat while the engine is running. The answer is quite simple. The engine uses a combination of anti-freeze and water to help keep it cool. The water is circulated by a water pump. The hot water moves through the heater core, which is a small radiator. The blower draws air through the fins of the heater core and heat is pulled from it. The water pump is usually belt driven, and the engine must be on in order for the coolant to circulate.

Car Smells
GMC Sierra
Car Heaters

What causes a burning smell from a car heater?

Could be many things. Can't say exactly what. But, here are a few things I would check. Do you have trees in the area you park your car? If so, you could have leaves pine needle or other dibree in you heater vent that could have caught fire from your heater motor. I actually had this happen once, it filled my pickup cab with wood smoke. It smelled like that every time I used the heater until I sold the truck. You heater core could have a leak and the antifreeze smell could be coming through your vents. Or your heater motor itself could be going bad and melting the winding on the motor armiture. I'm sure there could be other things like electrical shorts, lost cigar behind the ashtray. Hope that gives some help.

Heating AC and Engine Cooling
Heater Cores and Blower Fans
Car Heaters

Why would the car heater not blow any air?

Car Heater Not Blowing AirHere are answers from FAQ Farmers:
  • The duct fan is bad. Replace it. Beware though: it's a pain the butt.
  • After you replace the blower motor and it still doesn't work, take it to a shop for testing if you can't do it. Other possiblities are a switch, relay, resistor, fuse, wiring. You can eliminate the fuse by swapping it with another of the same. You can try the "tap test" by rapping on the dash sometimes over the glove or on the blower motor itself, somteimes a weak motor may temporarily start working. Oh yeah, all blower motors aren't bad to change.
  • If it's blowing air, but only COLD air, check that your engine coolant isn't very low.
  • Sounds electrical, check the blower motor relay, although it may be switch or motor.
  • This happened in my car! After replacing the blower motor (it wasn't broken afterall), found that it wasn't getting power due to a faulty ground. This was right behind the a/c heater radio console.
  • With the fan only blowing at the 4 setting indicates the resistor need to be replaced. The resistor controls the flow of electricity to the motor, w/ the 4 setting not limiting the current at all, which is why you the fan works at that speed. I'm in the middle of trying to fix my blower too, but so far no luck. I've replaced the motor, but nothing's changed. The volt tester shows power to and from the motor, but no movement. I'm not sure what else I can check at this point.
  • Is the fan actually running or not? Can you hear it...but no air seams to be moving? If yes, then one of the duct-work doors may be stuck. (There are little electric or sometimes vacuum operated door inside your duct work) A wire or tiny hose to one of these may be loose or fallen off. If you cannot hear the fan running at all, even on it's highest setting...then consider looking at fuses, loose electical connectors (sometimes they get kicked off by a passenger). It's actually rare to have a fan motor die...although it can happen.
  • This is a really easy fix, it's likely that your thermostat is stuck. This has happened to me on numerous occasions when I had rusty water in my radiator. The thermostat was stuck, so I replaced it and tada! You've got heat. Usually less than 10 bucks to fix.

what is the make and model and can you hear the blower motor running

American Cars
Heater Cores and Blower Fans
Ford Explorer Eddie Bauer
Car Heaters

What can cause a car heater to not work?

Answer I will firs verify is the climate control is working (the dash board) controls, and then work my way up to more complicated issues. There are to important by pass that could be clogged also, if water has been used instead of coolant.
well for one it could be the heater blower motor or it could be the control under the dash that changes it from hot air to cold air if the spring spring breaks it will not get hot.
Hope that helps Try changing the thermostat. If it is stuck open or failed, engine temp will not rise. I had same problem on 95 explorer, changed thermostat myself and solved problem. Answer
It could be the water pump but most likely the antifreeze is low and needs to be filled up to be able to circulate through the heater core.
need more info. you could be low on coolant.for all we know. there are alot of different parts to a cooling system which bring heat to the cabin area. start simple. ck fluid level make sure it is full when cold. 2. when running does it circulate through the hoses. 3. are your heater hoses hot. both. 4. does your fan blow in all possitions & does air come out from your vents?

A heating system works by diverting hot coolant through a heating grille where it warms up air which the fans blow in whichever direction and whatever speed you specify.
Basically there are two parts to the heater system, there is the heater tap, located in the engine compartment. It controls how much (if any) hot coolant goes through the heating system in your car. Probable causes are a leak in one of the hoses, the heating grille itself (you will smell coolant in the car) of the radiator is not sufficiently topped up with enough coolant to circulate through the system. If not turn your heater on to full, turn your car on for a short while, turn it off and top up the coolant. Also bleed the air out of the system if necessary.
The second part is self explanatory, the fans blow the hot air around the car if the problem is not with the first part above, it would be best to have it taken to an auto electrician.
first thing you need to check is your fuses .It is actually the heater motor, sam thing happened to my 2000 Alero
Ford F-250
Heater Cores and Blower Fans
Ford F-350
Car Heaters

Why no heat in cab of f350 diesel?

no heat can be caused by,blocked heater core

insufficient coolant in engine

blocked heater hoses from engine to heater core

bad heater thermostat

bad thermostat in engine

bad heater control switch

Heater Cores and Blower Fans
Car Heaters
Overheating (Engines)

Why would the car overheat but no hot air come from the heater?

You didnt say if the water pump was changed. No hot air means no circulation.

AnswerBrittany, You have 2 symptoms of a larger problem. It is like you said "I have a terrible headache and black eye." What happened was you missed the ball and it cracked you in the head.

Anyways, Coolant is a fluid that keeps a car from getting too hot among other things. If there is low coolant the car will overheat. When the coolant ciculates through the engine it will also go through a thing in the dash that is like a small radiator called a heater core. A fan or blower move air through this part and pushes the hot air from the heater core into the passenger compartment. This heater core is usually the highest point of the coolant flow. Since fluid seeks it's lowest level, the heater core is the first to lose the hot coolant. Therefore your blower blows accross a cold heater core and gives you cold air.

If you don't have a leak, then when the thermostat was replaced, the coolant may have not been bled of the air in the system.

I would first fill the coolant and check for any leaks first. There is a common problem with the Buick centuries if you have a 3.1 motor. The intake manifold gasket is common for leaking.

In any event, don't run the engine if it goes into the red. Overheating can cause headgasket problems. See othe posts regarding this issue.

Let me know how you make out.

AnswerGlad to hear your problem was resolved.

The heater core does not need to be removed to be checked. If the hose going into the heater core is hot and the one coming out is cold, the tells you it is retricted. Another way to verify is to remove the hoses going to the core, hook up one without installing into the car and run it. It should get hot-very hot, and then see how hot the hose is coming out of the core is like now.

AnswerIf this person that replaced the thermostat put it in backwards this could cause the car to overheat and the heater not to get hot. EzForJesus AnswerSimple - It is low on radiator fluid (water or anit-freeze).
Heater Cores and Blower Fans
Car Heaters
VW Sharan

Why would a car heater blow hot when the gauge reads cold and vice-versa?

Someone has either reversed the wires on the temperature gauge or damaged the wires from the engine to the gauge and spliced them back backwards. It is a simple reverse of polarity.

First, check your thermostat, your car may actually be overheating slightly due to the thermostat sticking. If it sticks then no anti-freeze flows through the heater core(providing the cab with heat), which will cause overheating. If it eventually opens, allowing flow, and cooling off the fluid/engine (gauge drops) then fluid flows again giving you anti-freeze through the heater core and heat pours out. Check it by removing it and putting it in a pan of water and boiling the water with a thermometer in the pan (try to hold them both off the pan surface with tongs, it may screw up your reading), watch close for the temp at which it opens, should be 180F, but check for your car.

Second step would be to check your water pump, low flow from a water pump could also cause the same problems.

After those two, "you're on your own kid"

Air Conditioning and Coolant
Car Heaters
Heating Ventilating and Air Conditioning

What could be wrong with your ruud central air system if it only blows but no cold air comes out of the vents inside the home?

It could be a low charge, but start by cleaning your filter and see if that helps. If the compressor isn't coming on, it could be burned up.

Air Conditioning and Coolant
Jeep Cherokee
Car Heaters
Air Pollution

What could cause a 1988 Jeep Cherokee air conditioner and heater to quit?

under the dash pass. side look at heater you will see a plug with several wires that look like thy go into the heater there is a one screw plastic cover over this area so your feet dont hit it remove then uplug the wires then take the 2 screws out of oval shaped sensor and pull it out of heater you will see some transister on the back side and a little coil . replacing this will cure it usually . but first remove your heater blower and make sure it turns freely and not seizing.

Heater Cores and Blower Fans
Car Heaters

How do you back flush the heater core?

Disconnect both hoses that go to the heater core from either end, (the end at the heater core or the end at the water pump, manifold, radiator, etc.) using a garden hose, preferably with a hose repair end attached to plug into the hose or a short piece of hose cut off to connect to the heater core, run water in each direction through the heater core until water runs clear, then reverse direction of flow. Repeat as many times as necessary until flow is restored and water runs clean. Be sure to also flush the rest of the cooling system or debris from it will likely just clog up the heater core again.

Mercury Grand Marquis
Turn Signals and Hazard Lights
Car Heaters

Why would fuse 16 for the directional signals blow on a 2002 Mercury Grand Marquis?

If this is the case, try disconnecting the ac compressor. If not that, it could be in the 'master switch' (turn signal lever unit). Does anything else go out along with the turn signals? Does it only happen when you turn on the heater or ac?


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