Hi. I'm having trouble with my AC coming on and I've about narrowed it down to the computer. Can I just swap the computer with one from a junkyard? I've already figured how to pull it out and re-install it. Thanks in advance. 5.7l

 

what have you done to rule out the pcm?
The pcm will withhold a/c turn on request depending on certain input data to the pcm. Go in with a scan tool and view the a/c request parameter and make sure its not withheld or you will be replacing a good part. pcm's are replaced incorrectly more often then not.

 

hi thanks for the quick reply. Yesterday with the mechanic, he used the scan tool to discover that the AC was being shown as not-on (no request). Also, we jumped the compressor clutch relay at the box and the system kicked on. (even with the low-pres cutoff switch in place). I've used a ohm meter to test that i'm getting voltage off of the back of the AC control head (light green wire) so it's not the control head. Not sure what else it could be.

 

does this year have a cycling clutch system or scroll compressor

 

Well, i know that it has a clutch-cycling switch and a clutch on the compressor. I do not thing it has a scroll. How can I tell if it does?