A/C Clutch & Cooling Fans Not Working- Related Issue?

[Casey]

'96 Cutlass Supreme w/150k miles on the odo...

 

After reading old posts and the FSM, directly powering the A/C compressor with hot battery power (sounded like clutch movement), and not finding any fuses nor relays obviously blown, I'm guessing the problem is low pressure in the A/C lines. Is there a way to by-pass/jump the low pressure switch:

 

 

...in the line from the condensor to the evaporator to get the A/C clutch (and cooling fans) to engage and come on? I see a red/black tracer, black and gray wires in the switch's connector.

 

A/C was never working and I've only had the car for three weeks, so no real history to go on.

[slick]

Only 1 fan is controlled by the AC. The other turns on at a specified temperature, via the ECM. Check your fuses and relay's.

 

Is your AC system just low on refrigerant?

[Casey]

Only 1 fan is controlled by the AC. The other turns on at a specified temperature, via the ECM. Check your fuses and relay's.

 

Which one? I did check all of the fuses and checked the #1 and #2 fan control relays.

 

Is your AC system just low on refrigerant?

 

I have no idea if it is or isn't low. The FSM states the PCM controls the A/C clutch and turns it off if the pressure is too low and controls the cooling fan operation. Seems to me that'd be a huge coincidence that both stopped working and weren't directly related.

 

Would I be better off just plunking down the $30 for an R-134A recharge kit at this point and seeing what happens?

[Casey]

I just re-filled the A/C refrigerant to the correct level and pressure range, and there's no change. Still no A/C clutch engagement and no #2 electric cooling fan engagement.

 

I did verify both fan relays and the A/C realay at UH center #1 are all good, and the drivers side fan (#1) came on when the temp got up to about 3/4 on the temp gauge, so I know that fan is working.

 

How common is it for the high-pressure switch to fail? FSM states it cannot be repaired, but rather must be replaced. I jumped the switch terminal's red and grey wires, and both fans engaged (#1 and #2), so at least the wiring to fan #2 is good. This leads me to believe the high-pressure switch is shot and needs to be replaced, since it works just fine when by-passed and the low-pressure side has approx. 45 psi in the line, which is where it should be.

 

Comments/suggestions? Will the all of the A/C refrigerant need to be re-claimed and re-filled when/if the switch is replaced? I'm guessing so, since I doubt there a one-way valve where the pressure switch threads into the ref. line...

[LuminaPower92]

I know its been a bit since this topic but wondering if you found the problem? Sounds exactly whats going on with my Z and was wondering about the switch as well, one tech told me there was a valve there and you didnt need to evac it, but replace it, but who knows. Just curious if you fixed it and found what was causing this.

[intern8tion9l]

my a/c hasn't worked for like 3 years.....system is full, brand new condenser. ever since the motor swap my compressor clutch won't engage. and it's been in the 90s.....needless to say i'm pissed

[89SupremeCutty]

if the compressor isn't coming on or engaging, how could you have put refrigerant in it? if you have the 3100, try using a jumper wire in place of the a/c relay. unless you have already done that.