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AC blows hot air

itsjsb on Sat May 10, 2014 12:02 PM User is offline

Year: 99
Make: pontiac
Model: grand am
Engine Size: v4

Why my wife bought this car a while back idk, but i would not had let her if she was with me at the time. She bought it from some kid who put rims and and all kinds of things with it, and ive slowly been fixing the stuff he did to the car for it has made it a mess of problems.

She said the AC worked when she bought it, it does not now blows nothing but hot air when dial is turned all the way to cold with ac button on... i figured it might need the AC boost, so i boosted it nothing... when i turn the ignition but not start it, it blows cooler air, but not cold, but as soon as i turn it on, it start blowing hot air. the dial is all messed up cold is hot and hot is cold, plus the dial turns past the mark all the way around back to the cold for cool air if you get the description... idk what it is i rather try and fix it myself if i could before taking it in, and spend a lot on something that could be fixed by me.

HECAT on Sat May 10, 2014 2:41 PM User is offline

So which problem do you want to tackle. The non-functioning a/c that someone may have contaminated or overcharged with some kind of DIY charge "boost?" kit? Or tearing out the dash to repair the broken control functions? Sounds like you inherited a nice car. Going to need to do some more study and testing on either problem to come back for guidance.

I don't know either; is it something that can be fixed by you?


HECAT: You support the Forum when you consider for your a/c parts.


Edited: Sat May 10, 2014 at 2:43 PM by HECAT

itsjsb on Sat May 10, 2014 4:26 PM User is offline

i should had stated that the panel is not a problem that is an easy fix, im just wondering what could cause the heat blowing through. it happened before i boosted it... so i know that is not the cause.. but from letting it sit for a while, i looked at the compressor, and it was dripping something out of it. i stopped loading the ac boost before the over load red part on the gauge.

mk378 on Sat May 10, 2014 4:43 PM User is offline

The dial controls an "air door".. How it is suppoed to work: The air from the blower first goes through the evaporator coil and hopefully gets cold. Then if the dial is on full cold, the air door causes the air to all bypass the heater core and go direct to the vents. If the dial is at other than full cold, some air goes through the heater and gets re-heated, so that more temperate or even hot air comes out. The heater will overpower the cooling power of the A/C if the door is not working.

You can tell if the refrigeration system is working by noticing if the accumulator and suction lines under the hood (between the evaporator and the compressor) get cold. That means the evaporator can make cold air, though it may not make it to the vents. The refrigeration may have actually been OK before you went to "boost".

Edited: Sat May 10, 2014 at 4:46 PM by mk378

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