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GM/Harrison - V5 compressor information?

kwandobe on Tue June 14, 2011 4:03 PM User is offline

Year: 1991
Make: Pontiac
Model: Trans Sport
Engine Size: 3.1L V6
Refrigerant Type: r134a
Ambient Temp: n/n
Pressure Low: n/n
Pressure High: n/n
Country of Origin: United States

Hello again! I was wondering if anybody is particularly experienced enough with this compressor to tell me what the two harnesses running to the back of the compressor near the refrigerant line would be? Is there a way to your knowledge these lines could be tested?

Thank you in advance =)

GM Tech on Tue June 14, 2011 5:04 PM User is offline

I assume you mean wiring harnesses.....correct?

They are to switches that monitor discharge pressure- one switch with light blue wire is the high pressure compressor cut-pout switch, the other is the cooling fan request switch- if head pressure hits 175 psi the cooling fan(s) come on.

PS- I'm dooing this from memory- should be right.....

-------------------------
The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

kwandobe on Thu June 16, 2011 3:26 PM User is offline

Thanks for the information, it should help =)

I've been trying to get this clutch to engage and spin my compressor up, but to no avail. I have 13+ volts at the clutch coil, have tried tapping on the clutch and it still wont engage. The coil reads 4.2ohms, but I read somewhere it should be between 3-4ohms. I think it's time to just replace the entire compressor assembly. Unless someone has some testing advice?

I have gotten the fans to come on by jumpering the high side switch, that's the best I've gotten so far! lol

Edited: Thu June 16, 2011 at 3:35 PM by kwandobe

JJM on Thu June 16, 2011 5:51 PM User is offline

Even if the clutch coil is bad, that still doesn't mean you have to replace the entire compressor; you can just replace the clutch coil.

Also, 4.2 shouldn't make or break. Try applying +12V fused directly to the battery - bypassing the vehicle wiring - if the compressor clutch now engages, it's the relay or wiring.
Having 13V at the clutch doesn't mean you have the necessary current to pull the clutch in.

Joe

When considering your next auto A/C purchase, please consider the site that supports you: www.ACKits.com



GM Tech on Thu June 16, 2011 8:12 PM User is offline

Bad a/c relay can act as you describe.

-------------------------
The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

kwandobe on Thu June 16, 2011 9:54 PM User is offline

Quote
Originally posted by: JJM
Even if the clutch coil is bad, that still doesn't mean you have to replace the entire compressor; you can just replace the clutch coil.

Yea I know replacing the coil is an option, though I have read that most times the compressor goes out shortly there after. So I'm not sure whether to trust it or not. Plus I'd have to buy the tool, don't really want to lol!

I will definitely try applying direct battery current to the clutch coil with what, a 10 amp fuse? I had actually given this some thought, was saving it for my last resort. But I guess I'm there already huh?

Quote
Originally posted by: JJM
if the compressor clutch now engages, it's the relay or wiring.
Quote
Originally posted by: GM Tech
Bad a/c relay can act as you describe.

When I visited the junk yard last time I pulled a couple A/C relays from the same make and model vehicle, I have since then tried them and it hasn't helped. Do either of you know if there are any capacitors/relays/circuit boards between the heater controls and the A/C relay? Or am I just going to have to replace my heater controls if I find my clutch works?

Thanks to both of you for your help =)

Edited: Thu June 16, 2011 at 10:29 PM by kwandobe

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