ac problem

[RLS]

My air unit in my 72 does not work all the time. It is properly charged and such. It seems not to get the proper amount of voltage to the clutch. The guy that worked on it, feels that a relay is out or is failing. He thinks its the anti dieseling relay which is somehow tied in the the AC circut. Anyway he worked on it all day to with no luck--good news he felt bad about not being able to fix it and did not charge me anything. He said it is one of the few times he has been stumped. Any ideas. I will add this - it just does not seem to get the proper amperage to make the clutch engage.

 

[Eric]

No input, just reviving this thread in hopes of an answer.

- Eric

 

[MaineShark]

Hmm... maybe put an ammeter and a voltmeter on the wiring to the clutch, and see what the actual readings are, then try the same on a car with known working A/C, and see if they are similar? That will at least let you know if your theory is correct.

Assuming the readings are significantly different, my first thought (given the age of these cars), would be to check the wiring and components for shorts.

Relays can be fairly easy to diagnose: run a wire across the terminals, and see if the problem goes away. If it does, remove the jumper and replace the relay.

Joe