Ac Delco Compressor

[Vetteguy]

I pulling my hair out, looking for the right A/C Compressor for my '77 Corvette. Every parts house web site I go on, including AC Delco's site. They are giving me 2 different part numbers, 15-20206 and 15-21764. Will both fit, the 15-20206 is saying something about a switch. I don't know what to order. I want an AC Delco unit, not an after market one... HELP

[Yallrun]

Do you have the original one? If so and giving the vintage nature of your Vette, I'd look for someone (Shop) to rebuild the old one. If the compressor has eaten it's self up I understand you wanting to replace it. Do you have a picture of your compressor? Your right there are 2 different styles.

[wascator]

some of the compressors have a switch added to the rear end (i.e. opposite the pulley end) and all I have seen at least have a spot for it. One wire connects to it as I recall and it may be the switch that cuts power to the clutch if the discharge gets too high, but not certain. Anyway It should be obvious if your car has one on its existing compressor, and I think the switch can be swapped to the new compressor as long as it is still good.

[wptski]

some of the compressors have a switch added to the rear end (i.e. opposite the pulley end) and all I have seen at least have a spot for it. One wire connects to it as I recall and it may be the switch that cuts power to the clutch if the discharge gets too high, but not certain. Anyway It should be obvious if your car has one on its existing compressor, and I think the switch can be swapped to the new compressor as long as it is still good.

The only way something with one wire can work is that it provides the ground for a circuit and grounding through an assembly, brackets, bolts, etc. is iffy at best. That why early O2 sensors with a single wire went to two wires because used the exhaust pipe as its ground path and all that rusty piping didn't work too good.

[Tim]

Do you have an A6 or R4 compressor? On that year both were made available.