There is a caseunder the dash that holds the heater core and ac evaporator core. In that case there are what are called blend doors. They are controlled by vacuum from the engine that runs to the doors through a diaphragm. The defrost/floor position is the default position that the blend doors automatically go to if there is a malfunction. Usually when that happens it is caused loss of vacuum. Another sign of a vacuum problem is when there is an apparent loss of air from the dash/side vent position upon acceleration which returns to normal when not accelerating. Annoying but harmless.
That means either you have air in your heater core or your heater core is being bypassed
if you got antifreeze on your windshield when you turn the heater on, it's bad
a heater hose runs from intake to heater core to radiator. the heater core is were the heat comes from inside the car as well as defrost
Yes they have a heater/defroster.
ihave a 1986 chevette that when i turn defrost on it blows out heat and when i put heater on it blows out only cold air? ihave a 1986 chevette that when i turn defrost on it blows out heat and when i put heater on it blows out only cold air?
The fastest way to defrost a windshield is to turn the defrost vent on without heat or simply open the windows. Another option is to warm the inside of the car by turning the heater on.
it should if you have the heater control in the defrost position this is to remove the moisture from the air
Blocked heater core, faulty heater valve, disconnected connection to the heater valve.
no, I placed a 100w lightbulb underneath the oil pan
Yes, the ac will run in the defrost position to dry the windshield.
Most likely a bad or disconnected vacuum hose to the defrost/floor selector in the heater ducting.
The most common thing will be that you have a leaking heater core...........
car cuts off
2001 dodge ram 1500 ac and heater flow regulator switch does not work. works only on defrost. How to fix?
Inside of the car. Remove the glove box.
If defrost is on it could be your compressor going bad. See what happens when you leave off defrost or disconnect your compressor. It only controls defrost and air conditioning. I had the same problem
More than likely its the defrost timer or the defrost heater. You can try and advance the timer which is usually located at the top of the refrigerator compartment. Its usually a small round circle with a slot in the middle. Take a slotted screwdriver and advance it till you hear it click then stop advancing it. This more than likely is defrost mode. It should kick on the defrost heater. Listen closely if you can hear the heater kicking on and sizzling the ice. If you do advance the timer to run after about 1/2 an hour and repeat the process until the ice is gone. If this works then the timer is defective and needs replaced. If this process doesn't work then the defrost heater is probably defective.
The compressor is coming on because you have the heater set to defrost. Take it off defrost and the compressor will not come on. I would suspect the compressor is locked up.
Blown Heater Core - The heater fan blows past the heater core and if it has a hole in it your antifreeze ios being blown onto your windshield.
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.
you probabally have a vacuum hose disconnected
the heater core is going out
usually you will get antifreeze smell and steam inside coming from defrost
you have a fuse out...
That's probably steam from a leaky heater core.