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Ron
Ron, ASE Certified Technician
Category: Cadillac
Satisfied Customers: 34793
Experience:  34 year as an ASE Tech
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A/C compressor wont' turn on JA: Sometimes things that you

Customer Question

A/C compressor wont' turn on
JA: Sometimes things that you think will be really complicated end up being easy to fix with a Cadillac. The Cadillac Mechanic I'm going to connect you with knows all the tricks and shortcuts. Tell me a bit more about what's going on so he can help you best.
Customer: There was a problem with the radiator.. Got a hole in it.. The A/C was working just prior. once I replaced the radiator an then the A/C stopped working
JA: Are you hoping to fix this yourself?
Customer: YUp.. It's GOT to be something very simple
JA: Great! What have you tried so far?
Customer: checked all fuses and buss terminals and even bench tested all relays
JA: Is there anything else important you think the Cadillac Mechanic should know about your Cadillac?
Customer: 1994 cadillac devile concours STS
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Cadillac Mechanic about your situation and then connect you two.
Submitted: 1 year ago.
Category: Cadillac
Customer: replied 1 year ago.
As i wrote B4.. The Radiator had crack in it.. I replaced it. The a/c was working just prior and now the compressor won't turn on.. There are NO codes that relate to that Freon being low or anything to that regard
Customer: replied 1 year ago.
When I hit the off and heat button I get PCM?
Customer: replied 1 year ago.
All fuses, buss terminals and relays all check out and have continuity
Customer: replied 1 year ago.
Nothing makes sense?? All wiring appears good. All sensors are connected on high and low pressure lines..
Customer: replied 1 year ago.
codes I do get are SO61, SO71,SO72 & SO73 AND LASTLY PCM WITH "?" ATTACHED TO IT!
Customer: replied 1 year ago.
and those codes have to do w/ suspension.. I am baffled????
Customer: replied 1 year ago.
Just checked BOTH electrical fans. They appear to be hooked up correctly also
Customer: replied 1 year ago.
I need to pick up my kid @ the park..Be back in 15 min tops...my Cell # ***** in case(###) ###-####
Customer: replied 1 year ago.
I'm back!!!!
Customer: replied 1 year ago.
I'm back!!!! Lost power...
Customer: replied 1 year ago.
Well?????
Expert:  Ron replied 1 year ago.
Hello, my name is ***** ***** I am a professional here at Just Answer. I have noticed that your question was not getting a response and thought I would see if you still need help with this.I apologize for the delay and I hope I can still assist you with this here.The first thing you should try before you do anything is to reset the system, to do this remove the negative battery cable for a few minutes and then reconnect it and start the engine and recheck the compressor operation. Give this a try and post back if that dose not correct this and we can work from there.
Customer: replied 1 year ago.
I tried that... Still no A/C!
Customer: replied 1 year ago.
The FAN works in the car but the compressor does NOT kick in!
Customer: replied 1 year ago.
All I did was change out the radiator??
Customer: replied 1 year ago.
Any OTHER ideas???
Expert:  Ron replied 1 year ago.
Dose the compressor run if you jump the low pressure cycling switch?
Customer: replied 1 year ago.
After about 5 seconds the compressor kicks in when the switch is jumped
Customer: replied 1 year ago.
However no cold air comes out?? How could this happen when changing out a radiator??
Expert:  Ron replied 1 year ago.
Okay then if it runs by jumping the low pressure switch then you may be low on Freon, hook a set of gauges up and read the pressure with the switch jumped and the compressor running, normal pressure on a full system need to be right at 35 to 40 PSI on the low side and 200 to 225 PSI on the high side. Check this next.
Customer: replied 1 year ago.
I do not have gauges.. Low on FREON??? How could this happen when changing out a radiator??
Expert:  Ron replied 1 year ago.
Im not sure but if you jump the switch and the compressor was running the system should have gotten cold. If it did not then the next steps would be to check the pressures.
Customer: replied 1 year ago.
I'm @ work now.. Is it possible that when I changed out the radiator a fitting loosened up?
Expert:  Ron replied 1 year ago.
I would sure suspect that is the case. The low pressure switch is designed to shut the compressor off if the system is low on Freon.
Customer: replied 1 year ago.
That's just great.. Now I NEED TO find THE LEAK!
Expert:  Ron replied 1 year ago.
Well before you get that involved lets get the pressure checked.
Customer: replied 1 year ago.
I had a can of 134C Freon with a gauge on it. I put whatever I had in system. Now the compressor kicks on and of with 20lbs of pressure.. I'll get another can and add that up to 35-40 PSI...That should do the trick.. I checked ALL the fittings and hey are all snug and tight..Just still wondering how this could have happened while changing out a radiator??? Any Ideas??
Expert:  Ron replied 1 year ago.
Its is odd that the system is low if you did not open it up. If you did not open any lines then you have to have a leak Top it off and lets see if it holds.