a/c problems
 

i dont know much about ac systems. this question will probably sound very basic to most of you. My 1980 sc has an updated (beefed up for AZ weather) ac system. everything worked fine. i only used it sparingly here in CO. as of last week, it blows warm air out of ac vents. when i turn the swtich on, the rpm dont drop at all. where should i look?

It could be a lot of things. Fuse, low coolant (if you have a hi/lo switch to cut off the compressor), the AC switch itself may be bad.
Does the compressor clutch kick in and cause the compressor to turn when you turn the AC on?

checked the fuse, it was fine. i dont think the clutch kicks in, that would cause a drag on rpms right? when i turn it on the blower kicks in, how could i check the coolant level?
thanks for your reply

You're out of freon. There is no high/low limit switch on these cars so the compressor will run without freon in the system.

If there's no freon, there's no load on the compressor.

With the engine running, turn on the a/c to max, go to the back and see if the compressor is turning.

Don't run the a/c very long w/out freon, as the freon is what's carries the lubricating oil for the compressor. If no freon, no lubrication.

Get it recharged.

I'm saying freon, because that was what was used in the car from new.

It could have been converted to 134a, though, in which case you can recharge it yourself.