Air conditioner problems on '81 Buick Riviera w/307 engine

[noreastcarnut]

:confused: I'm unable to get my a/c running on my '81 Buick Riviera. I tried to recharge the system to the proper pressure with the current Freon. The compressor does not kick in. I tried jumping power directly to the clutch, but nothing happens. Also, there is no live power in the wires to the clutch with a/c controls in the proper setting. I'm stuck and it's very hot here! Any help appreciated!

[Guest pfloro]

With the engine NOT running:

1) Disconnect the 'two prong' female connector at the A/C compressor clutch.

2) Ground either of the male prongs on the clutch.

3) Connect the other directly to the battery '+' terminal.

You should hear a clack and see the clutch plate pulled toward the firewall. If this occurs, the clutch's electromagnetic function is working. Repeat the above steps with the engine running.

With the clutch engaged, the compressor internal components should now turn. If the clutch doesn't energize, it has an internal electrical 'open'. I believe that the clutch can be replaced on these R-4 compressors without removing the compressor from the car or evacuating the system.

If the interior A/C 'control head' doesn't energize the compressor clutch, there is something amiss between the clutch wiring harness and the control head itself. Get the 'Electrical Troubleshooting' manual for your car. This has detailed multi-color wiring diagrams as well as diagnostic procedures. While I owned my '84 Toronado (28 years), this manual proved invaluable in keeping the electrical systems in tip-top working order.

Does your Riviera have electronic climate control? If so, one or more of the embedded electronic components in the control head may have failed.

Keep in mind that getting the compressor to turn is only the first step in getting a functioning A/C system.

Good Luck,

Paul

Edited July 17, 2012 by pfloro (see edit history)

[noreastcarnut]

Thank you for the suggestion. I did try to engage the clutch directly and it works. However, there is no power in the line there. I have replaced the control head as there was a vacuum leak and the lever was jambed. Now all is free. As I ran the Riviera again, the clutch did cut in and off for some time, but not steady. I did add another can of Freon, but it still did not run steady nor did it get cold. I do have the shop manual and am trying to figure it out.

[Guest pfloro]

Since the compressor is 'short cycling', the system is either low on refrigerant or the flow of the refrigerant is not proper. It's time to have an A/C specialist put a gauge set on the system & check the

pressures. This can reveal much about what is going on.

Paul

[noreastcarnut]

OK, I guess I'll just have the system evacuated and redone with the new 134 fluid. Thanks guys!

[Larry Schramm]

I would not just put some more refrigerant in the system. The system needs to be checked for a leak which is starting with the basics. If the system is holding pressure with the engine off and it has the same pressure a week or two later then the system is probably fine. A set of gauges connected with the engine running will tell a lot about the condition of the refrigerant side of the system.

Then look at the electrical issues.

I think I remember a compressor clutch relay controlled by the control head. That is one thing that will keep the compressor from engaging.

A bad ground for any of the components will keep the system from working.

A bad low pressure switch would keep the system from working.

.... and the list goes on.

Best suggestion is to start with the obvious simple items.

[noreastcarnut]

Hello people: Thanks for the assistance. I did get the system evaced and replaced with R134a and it works just fine! The garage did add oil also. I am now cool and happy! I will drive from eastern Massachusetts to Troy NY Buick club meet on Friday the 17th.