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Are these problems related


jgeorg
07-08-2016, 06:55 PM
The ac on 2001 limited is blowing warm air and compressor not engaging. Also neither of the 2 fans are coming on and I recall that both would run when the ac was running. Are these problems related. I'm guessing the ac clutch isnt engaging because of low coolant pressure. Would that cause the fans not to run or is it vice versa, fans not running causes the compressor not to run/engaged.

Tech II
07-09-2016, 08:51 AM
Naturally, if the compressor is not running you are not going to get cold air.....

Cooling fans only come into play after, the compressor runs.....for example, if the compressor runs, pressure and heat will build up, and the pressure sensor will "sense" this, and send a high pressure signal to the PCM, which will shut down the compressor....if a code is set, then the compressor will not engage again until the problem is fixed....but your fans will not run, until that compressor engages, so if it doesn't, you have no cooling fans for A/C.....

But the cooling fans must be working, because you are not overheating......

So chances are you are low on refrigerant, and if you are, the pressure sensor "senses" this, and tells the PCM, you are low on it, not to engage the compressor.....

With the system at rest, and on a cold engine(not started), with a set of pressure gages on the lo and hi sides, pressure should approx. be equal to ambient temp.....so if it is 80F outside, your pressures should be equal, and approx. 80 psi...... lower and you know you have a leak......you can have close to 80 psi, and the compressor may not engage, if a code was set......if you clear the code, then the compressor will run, but if the low side drops well below 30 psi, the compressor will shut down, and the code will set again.....there is refrigerant in there, but not enough to handle any kind of a load.....

brcidd
07-09-2016, 10:17 AM
I agree with Tech II- in simple terms-- GM "H" cars as is yours wait on 175 psi a/c discharge pressure to turn on fan(s). Since a/c cannot produce that amount of head pressure (due to loss of refrigerant) the fans stay off.

Typical leak location on your V-5 compressor is the belly of compressor...

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