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Ac conpressor not gettin power

beattie

beattie

New member
Ok i have a 2004 grand prix gtp and my ac compressor kicks in when it wants.. Ive change my pressor switch..ive changed the cord to it. Ive changed my dryer and refilled the freon... Ive traced the wire from the compressor all the way to fuse box.. Ive checked fuse relays amd the one diode... Ive also change my heater/ac switch inside my car.. Now heres what it does... If i leave my car run about 10 min at idle with my ac switch on sometimes it will kick on... Other then that the green wite from the compressor i can jump a wire from that to positive on battery and it kicks in... As soon as it kicks on i can disconnect that jumper wire and the compressor will stay working... Even if i **** off the switch in the car it will turn off and on when i hot the switch.... But if i shut it off for 10 min or so or shut the car off the ac is back to not workin... So ill either have to wait 10 min or so with car at idle or jump the positive wite and then remove the jumper wire and it will work.... Ove had it tested it has the right amout of freon and doesnt have high pressure... My question is what else could possible not sending it the power when i hit the button... Bc im gettin stumped on this....... Thanx in advance
 
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The request goes to the pcm. The pcm looks at exterior temp and other things. Then the pcm kicks on the relay to give it power.
 
So do you think my pcm is messed up or something else.... Ive unlplugged the sensor behind the grill that i thought was my outside temp.. But even with it unplugged my insise temp still worked..... Basically askin what i need to do to get it to work
 
I think you have bad relay probably the contacts are burned out, it's sending enough current to hold it in but not enough to pull it in. When you jump it, it allows more current to flow and keep the clutch held in.

Try swapping relays.

Jeff
 
I should have been more specific.. I have changed all the fuses ive changed the replay and ive change the 1.0 diode .... Ive done everything possible
 


Bill is saying the pcm looks at other sensors to determine if the ac should be on or not. Maybe one of the sensors its checking is faulty?
 
Well you said you unplugged what you thought was the outside air temp sensor. Since it still reads something you obviously unplugged the wrong thing, however, does it read correctly?
 


Also i didn't think of it but if my tps sensor was bad i would have to repalce my whole throttle body i think... Since its one unit on the 04+
 
Do you have a meter? You could measure the voltage at the plug when this condition occurs. Also measure the resistance of the clutch coil.

Jeff
 
There's all kinds of stuff that could keep the pcm from turning it on.

Say the coolant sensor tells the pcm that it can't see the temp of the engine by defaulting. PCM isn't going to potentially cause any more heat in the engine by turning on the AC. Say the exterior temp sensor is faulted, that can cause it. While you are going around the system by jumping it, that's a bad test because it's not telling you why the system won't turn on.

You need to see if the HVAC is requesting and the pcm isn't allowing. Meaning..you need to understand the system on an factory service manual level to know what is causing your issue.
 


Ya im guessing im gona have to break down and take it to dealer to get it scanned... The hvac i one of the things i changed amd it didnt help... I took that out of a friends car just to see if that was the problem and it wasnt... Bit thanx everyone for the advise.. I just wasnt sure if anuone experienced the same problem and i could fix without going to dealer
 
Wait a minute, wait a minute. What is the resting pressure with the system equalized? What are your pressures on high side and low side when it is working?

Jeff
 
To get the numbers if have to go get it checked again but i kno when it was hooked up they said both gauges were readin where they was suppose to
 
if your low on Freon, or the high pressure switch sensor is not working the compressor will not work, (the high pressure sensor tells the compressor to turn on or not) or work on/off like your saying it does.


if its low when you recheck it its got a leak somewhere. and that would explain a lot.
 
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