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HVAC doesn't work unless hot outside

959 views 3 replies 3 participants last post by  Sharpie26 
#1 ·
Hello all, hoping someone can help me out with this issue. My whole HVAC system seems to work intermittently according to the temperature outside. When I start my car in the morning or in the evening when it's only in the 60s or 70s... the HVAC system does not work at all. The only thing that operates is the blower motor knob (all positions work) but none of the other lights, light up or function. The temperature control, AC* button, actuator doors and rear defroster do nothing. By the time I leave work or use the car in the afternoon when it's extremely hot in the car and outside (80's - 90's) everything lights up and works perfectly fine until the car is shut off. If during that drive the temperature drops down outside, when you shut the car off then the HVAC will not operate when you restart the car. If it is still extremely hot outside when you shut the car off... then the HVAC unit will still operate as it should when restarted. This is the manual knob HVAC unit and I did replace it already which changed nothing. Is there some kind of temperature sensor in the circuit that disables everything when it goes bad? I did hit a deer back in Spring which was within a month of this happening... which crunched the front bumper and grill up pretty good. I see a small sensor hanging from a wire under the grill area but not sure if that's just an airbag sensor or something (they did not deploy). Any help is greatly appreciated!
 
#4 ·
Yes. Sensor is the ambient temperature sensor. Unless it's an airbag sensor but that will have blue lockout tabs on the harness plug. A long time ago I tried to "charge" my ac with one of those cans from auto shop. It ended up adding a bubble of aerosol in the ac system. I had to bleed it back out. I was getting into trouble then and left alone after. But I'm wondering if your ac has air getting into line after your deer accident. Keep us posted.
 
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