03 SE Bonneville- I have 12v at the compressor clutch, but the ground does not test out ok. also the electric fan does not come on when I turn the ac switch on. Not sure if they are related. I have a 96 olds 3.8L wiring diagram and it appears to be the same. there is a clutch diode about 6in into the wire harness. Has anyone ever had a failure of that and the ground is open? Since I have 12v at the clutch, I know the relay is working and I have enough freon at the pressure switch. I plan to troubleshoot the fan soon. I do not overheat, so the fan should be working. It did not get hot enough to warrant the fan to come on, but I will do that soon. any ideas on the ground? has anyone ever had a bad ground? splice? the end spot for the ground appears to be a common ground at the right side door pillar and is common with many other systems that are working. any ideas? thanks

I powered the clutch from the battery and known ground and the compressor runs fine and I get cold air. the electric fans kick in too, so they are operating fine, they must need a certain signal from the ac when the compressor is on- pressure switch I assume. so since I have 12v, it is definitely a ground problem I need to find. I am still looking at the diode. I will check the ground before and after the diode. I pulled a harness from a junkyard and opened it up, so I know exactly where the diode is in the harness. I received no inputs from anyone, so I think this is new territory. I cannot imagine how all of a sudden I have a bad ground, especially since no other system has issues. the ac worked fine last fall, then after the winter no ac.

I haven't run into that problem, but perhaps this schematic will help. You can compare it with what you have.

_________________
*Gone, but not forgotten* - Black 2000 SSEi, HIR Headlights, Angel Eyes fogs, 3rd brake light overlay, hi-flo cat, 180 degree thermostat, HS 1.9 rockers, LSx yellow springs, Intense FWI, PCM, shift kit, push rods, and 3.4 Pulley. ZZP Power Log.

very similar to the 1996 diagram I have, but the ground G100 is different, does it tell you where that is? I plan to follow the harness back, jiggling and getting to the final ground if I can. or I may just run my own ground after the diode. thanks for your help and sending the diagram, nice of you to do that. I usually have the gm shop manual for each of my cars, but decided the 96 manual is close enough to the 03 bonneville.

This is what it shows for ground 100.

_________________
*Gone, but not forgotten* - Black 2000 SSEi, HIR Headlights, Angel Eyes fogs, 3rd brake light overlay, hi-flo cat, 180 degree thermostat, HS 1.9 rockers, LSx yellow springs, Intense FWI, PCM, shift kit, push rods, and 3.4 Pulley. ZZP Power Log.

way different from my 96 manual ground location, I will check it out and let you know, thanks alot

Good luck.

_________________
*Gone, but not forgotten* - Black 2000 SSEi, HIR Headlights, Angel Eyes fogs, 3rd brake light overlay, hi-flo cat, 180 degree thermostat, HS 1.9 rockers, LSx yellow springs, Intense FWI, PCM, shift kit, push rods, and 3.4 Pulley. ZZP Power Log.

I did not have the grounds as the diagram showed. I ran a new one after the clutch diode. AC works great. I almost bought a new compressor before checking the ground. Reminded me to check basics before replacing parts.