A/C wiring question

[dr5375]

Hi everyone, I have a problem with my 87 S15. I changed from a 2.5 to a 283 and used a wiring harness from an 88 blazer. The only thing I can't figure out is the a/c. The truck was all original when I got it and I reused the compressor and other accessories. It does not have a low pressure switch on the accumulator but has a switch with a small round plug on the rear of the compressor. How can I make this compressor work?

[Melonhead]

Hi everyone, I have a problem with my 87 S15. I changed from a 2.5 to a 283 and used a wiring harness from an 88 blazer. The only thing I can't figure out is the a/c. The truck was all original when I got it and I reused the compressor and other accessories. It does not have a low pressure switch on the accumulator but has a switch with a small round plug on the rear of the compressor. How can I make this compressor work?

The switch on the compressor is a high pressure cut off. You need the low pressure to cycle off the compressor to not freeze the system. If you look at the 4.3 dryers, they have the switch mount to the dryer.

[355V8S10Tahoe]

You should have two low side service ports on your accumulator, just get a low side cycling switch and screw it onto one of the low side ports and wire both the high side and low side switches in series with your clutch relay circuit and you should be good to go...