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Why does AC and heater blow air through defrost vents and will not blow air into cabin vents on 2000 Ford E350 van?
There is a vacuum switch that controls an air gate that diverts the air flow to the proper outlet. Blowing air out the defroster is the default setting of the switch. Most common causes of this problem are vacuum leaks. Check the vacuum hose on the passenger side engine compartment first. It ususally leaks going through the fire wall. Regardless this problem is most often always the result of a leak somewhere in the vacuum system not the failure of the switch itself. If it is a diesel check for proper operation of the vacuum pump
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Why does AC and heater blow air through defrost vents and will not blow air into cabin vents on 2002 Oldsmobile bravada?
If the AC and heater in a 2002 Oldsmobile Bravada are only blowing air through the defrost vents and not into the cabin vents, it could be due to a malfunctioning mode door actuator. This actuator controls the airflow direction and may be stuck or broken, preventing proper airflow to the cabin. Additionally, a vacuum leak in the HVAC system can also affect the distribution of air. It's advisable to have the HVAC system inspected to determine the exact cause and resolve the issue.
Why does AC and heater blow air through defrost vents and will not blow air into cabin vents in your 2009 Mercury?
If the AC and heater in your 2009 Mercury are only blowing air through the defrost vents and not into the cabin vents, it may be due to a malfunctioning blend door actuator or a problem with the HVAC control system. The blend door actuator controls the flow of air to different vents, and if it’s stuck or malfunctioning, it may be directing all air to the defrost vents. Additionally, issues with the climate control module or vacuum leaks in the system could also cause this problem. A thorough inspection of the HVAC system is recommended to identify the exact cause.
Why does your trucks defrost vents start smoking?
That's probably steam from a leaky heater core.
Why heat blows out vents only not defrost or floor?
Most likely a bad or disconnected vacuum hose to the defrost/floor selector in the heater ducting.
Why does heater defrost vent not open on a 1989 Sunbird and cold air blow from dash vents but no air blows from heater defrost vents and where are the enter and exit hoses for the heater coil?
I don't know why the vent would not open for the defrost, but it may be related to the fact that your heater core is blown. If your getting nothing but cold air out of the vents when the heat is on, your core is finished and if the core is finished then it is likely related to your vent not opening/switching. Something''s wrong with your heating either way.
What could be causing a Glue gun-like smell in cabin of your 1992 Honda Accord LX?
Over time debris and other things can collect near the heater core, its possible that something small and plastic has fallen down through the defrost vents and gets hot when the vehicle is running. You may need to disassemble the heater and remove the items and perhaps vacuum it out.
Why is there no air coming out of vents can hear air blowing under dash board?
The year, make and model would help but many vehicles use vacuum to operate the direction of air flow through the floor vents, dash vents and defrost vents. If the vacuum supply is cut off for whatever reason the system defaults to defrost only. So if you only have the defrost mode working chances are the vacuum supply is cut off. Check the HVAC vacuum supply line under the hood for damage. If that system seems to be working but you have insufficient air flow through all of the vents, check/replace the cabin filter if applicable.
Selector only stays on defrosted 92 buick?
If the heat selector will not switch from defrost to the dash or foot vents on a 1992 Buick, it is possible that the cable connected to the vent is broken. When the selector is moved from defrost, a cable opens the other selected vents on the heater.
What causes the front air conditioner on 1999 Lincoln navigator to stop blowing through the ac vents and start blowing through the defrost vents?
When there is a problem in the vent system it defaults to defrost setting. Check the doors & vac supply
Why do you get hot air at floor and defroster vents but only cold air at the dash vents vents in a 1995 chevyvan 20?
the middle vents only supply air from the ac unit using a separate in dash fan. the floor and defrost vents come only from the heater
What is the difference in a cabin filter and a air filter for a 2008 Cadillac dts?
Most people when they say "air filter" are referring to the engine air filter. Cabin air filter cleans the air that comes into the car, goes through the heater core or air conditioner and then out through the vents into the cabin of the car.
How do you know which heater core you need to replace on a 94 ford aerostar front or rear you have heat but no defrost and stream comes out of the vents when heat is on?
Front heater core is in the dash, the rear heater core is all the way in the back of the vehicle. If you have steam coming out of the dash vents, the front HC is leaking. If you have steam coming out of the rear heater vents, then the rear core is leaking.
