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1981 AC Help Needed.... PLEASE.

Started by 80redcoupe, June 28, 2022, 05:29:08 PM

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80redcoupe

Team,

I have my car running GREAT!

I was charging the ac and got impatient..... Compressor came on and was cycling normally. I jumped the connector at the compressor to keep it running and charge faster. That's where things went wrong. The compressor stopped working.... I now have no power to the compressor anymore.

I assume that I cooked something. The blue wire at the resistor should have power as it comes out of the bulkhead connector. There is ZERO.

I have swapped in another ecu, programmer and the resistor. Still nothing. I substituted a control head for an 84 and got zero!

I am completely lost on whet to check next. The blower motor works, and the displays all light up. I can adjust the temp and see the programmer adjusting the arm.

I went in and applied power to the blue wire, compressor kicks on. I just cant figure out why it wont do it on it's own.

PLEASE HELP!

I have checked the cyclic switch and get 4 volts on the gray/white wire coming out of the bulkhead. The one coming off the resistor has 10.5 volts.

I have asked on another forum as well. Not trying to cause problems.... BUT... it is over 95 here and really need AC.

Thanks!
R Clerie

Dave Shepherd

You may have overcharged the system and one of the pressure switches failed, but what you are finding says differently. Shop manual has a good trouble tree for ac issues.

"Cadillac Kid" Greg Surfas 15364

If you have a superheat thermal fuse you may have popped that when the system was short of refrigerant
Greg Surfas
Cadillac Kid-Greg Surfas
Director Modified Chapter CLC
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-

Dave Shepherd

Good point, I think 81 may have had one.  Worked on that system back then, but memory has faded. Lol

81 BENY Biarritz

This is from the 81 Cadillac Service Manual.  You also need to use it in conjunction with the ECC Wiring diagram that is shown on Page 1A-52 for your car.  Hope it helps.  Dave 20220628_222532[1].jpg