A/C Compressor engaged 100% of time
 

Hello,
I have a 98 C2500hd, 5.7 vortec auto. 322K... The a/c compressor was fine untill the truck was involved in a hit and run. It was hit L/S front, hard enough that my truck was knocked up onto the curb from the street. Well every since that the A/C compressor is always engaged. I pulled the relay, the dash controller, low and high side switch connectors and still engaged. So I pulled the fuse from the main box {under hood} and that shut it down. looking for ideas on why? could the clutch in the Compressor be damaged from the hard hit? Thanks

You did what I was going to suggest, but I was going to just ask you to unplug it. That would isolate it being a control issue. Yes, it's mechanical issue with the clutch.

But if it is mechanical... would the clutch not still be engaged even with the power disconnected? I am just pulling straws...

Yes, that's what I why I would have suggested isolating it from an electrical control issue.

Okay the ac compressor is still, clutch engaged as long as there is current. I have replaced the compressor and clutch and still the same issue. I have unplugged all controls to compressor and still engaged. somewhere the unit is still getting power from somewhere, I have resorted back to pulling the fuse.

Was this issue every solved?

No it is not resolved.... the compressor is still engaged as long as it is plugged in. I have removed the fuse,

the compressor clutch is turned on by the pcm. It grd controls the control side of a relay to cycle the clutch. If the grd wire was damaged in the accident and shorted to body grd...the clutch will turn on anytime the key is in run.

install the removed fuses. key on, disconnect the a/c clutch relay. plug it back in...if the relay clicks, its being powered on so check the control wire for a short to grd.

remove the relay, disconnect the c3 connector at the pcm. check for short to grd on pin 1 connector c3 at the pcm, dark green/white tracer, wire colour

if the vehicle was repaired at a bodyshop; this is hidden damage. take it back and they will repair this and charge the insurance company.

Ok, thanks