All the grounds are good. Verified that. Narrowed it down to the Alt. Tested it with a meter just awhile ago. Nothing but the truck running at idle, its pulling 20 to 25AMPS. With wipers, headlights, heat, and emergency lights going, its doing maxing out at 50 amps. My truck is basic as it gets. No AC. No power steering. No power nothing.

I just went ahead and ordered a new alt thats supposed to come in tomorrow. Update this again tomorrow.

 

Alt was most def the prob but there was one bigger prob that has been taken care of and now runs good, and compressors run fine.

Since the trucks basic with no a/c, power steering, or anything good like that it was lacking atleast 1 ground. We added the ground in the back and now it runs good and the wires arent heating up. Just remembered what s10s we have worked on and they showed the same problems and they always have the back ground.

Thanks for the help guys. =)

 

Ok new prob. I got the fuel pump prob sorted out. Had to add a ground in the rear to the frame from the wiring harness like a s10. Well now the wiring in the cabs getting hot and to beat it all i think its the ground in the cab =\. It didnt start this problem untill yesterday. We've had teh comps fill up atleast 10+ times and it never happened.

 

What kind of current draw are your compressors rated at? Running 10+ times could be taking a toll

Also, you never mentioned where you're tapping power for the pressure switch. You also mentioned that you're running 4-8 awg wire for power. 8 awg is too small for compressors. If you're tapping from the dash, it could be just that. If I were you I would run 4awg throughout the compressor system including main grounds and run straigh to battery.
Good luck

 

sounds like you are missing body grounds...again

 

I have the compressors hook up on the relays, then the relays are hooked up into the distrubution block i have that runs to a 8awg, thats wired straight to the battery. The compressors are only drawing 29amps not sure on voltage. its the Viair 400c dual pack. The pressure switch is wired straight to the battery on a switch for right now until i can get all of this sorted out, so its just like being ran to a keyed source, but its constant power.

I added another ground inside the cab from the wiring harness. It helped in my fuel pump case but its not working in this case. Ive looked online for all my ground locations and could only find ones for under the hood. id love to be able to find a wiring diagram of the whole wiring harness.

Something else thats weird about this new situation, the main wiring harness connection in the cab thats located under the pass side of the seat the half coming from the back of the cab is normal, but beyond that connector its getting hot from the connector to 1 or 2 foot into ground wiring then it just ends and nothings wrong from there on.

 

dillinja666, you was right, but it wasnt a body ground. Just added a ground from the battery to the engine then the frame. It completed it as far as we know, didnt notice anything getting hot.