So those wires aren't shorted anywhere from the PCM to where there cut? If that's the case, I can't think off where to go from here. Possibly take it up with the EFI-Live guys and see if they have any insight.

 

Damn, yeah those wires are free from everything not touching anything at all. Ok I'll check their forum. I posted something there about it but got no replies but we'll see what happens. Anyway, thanks for all your help. Ill let you know if this ever gets resolved.

 

Im gonna try one last thing and remove the other A/C wires from red. The low switch at55 and the A/C compressor at 43. Actually, looking at this diagram you have... does the Low pressure switch supply a ground to the 55pin or does it receive ground from 55? If it supplies it, maybe the connection is messed up there? Like the fans were kicked into high mode and the low side blew out never supplying the ground to turn them off???

 

It supplies ground when the A/C pressure is above around 20PSI or so. It's there so the PCM stops the compressor is the refrigerant pressure gets to low. No refrigerant = No oil and the compressor would burn up.

 

Ok thanks again...Im still waiting on replies on EFi Live forum...I might just have to email customer service or something and see what they have to say. I read somewhere else another person having similar effects when they start the truck the 42 is supplying ground but when they reach a certain speed it turn them off. Something about the PCM not having the correct pressure for the AC so it always defaults it as on!?!?

Im thinking now though that, that probably isnt my issue being that i disconnected 11 /17 /55 and am still having the same issue. Good thing i dont ever use the A/C

 

Ok here's something that I completely forgot about. Back when that nelson harness blew up in 2006 I posted a thread for help in EFI Live forum. I completely forgot about it because I never got any help lol. Heres what i posted though and I wonder if this has anything to do with it....

" DTC B1000 and U1500!!!!
what does it mean, aside from the obvious I 'm trying to figure out what may have caused this. Last thing major that happened before this code showed up, my E-Fan's stopped in the middle of driving. I pull the harness to check it and the 1st Relay is FRIED. Wonder if this has anything to do with the PCM??? I also noticed that my so called ground wire(green/white) for the A/C is acting a little wierd...when I hook it up to the connector for the wiring Harness it turns the fan on while the A/C is off!!!!!...When the A/C is ON, it will turn the fan back off???!!!!??? Also wierd the fan will run when the truck is off when its plugged into the A/C wire!!! Once I take it off the A/C wire it shuts off any suggestions?? Is it possible to Put the A/C wiring harness on backwards on the A/C side itself?? "

 

Well, I tried EFIlive and i got some good insight as far as the tuning side goes...back to square one cause the OS that works for these trucks, still has the same result when i full flahsed my PCM. Anymore ideas electrical!? As I understand there is an ECM and PCM, whats the ECM's function in this whole setup? Possible that HVAC communicates with it and the PCM???

 

what was the outcome to the troubleshooting.. I had a nelson harness and the exact same problem. I installed a new ls1fans.com harness and the fans come on when the truck is off. So I hope you figured it out