2000 ZR2 blows main ignition B fuse repeatedly
 

My good friends ZR2 is repeatedly blowing the main 50 amp ignition B fuse when ignition is turned on. No gauges or dash lights, no ac or fan motor. Truck runs great and no codes. No problems with the engine or transmission.

- Grounds look good. Double checked
- Replaced ignition switch behind key cylinder.


Do we pull up the fuse box and look for corrosion? Any help is appreciated. Trying to find a wiring diagram for specific fuse.

Wiring Diagram:

2000 Blazer Power Distribution PDF

No luck so far. Blew three more fuses at $4 each in our attempt to unplug and check the wiring along that 50 amp circuit. It blows the fuse immediately when it gets power in the acc position.

The dash was out 7 months ago to replace a heater core. Everything has been fine and we cannot find a pinched wire.

OK, so main 50 amp ignition b fuse is killing power to the, AC, fan motor, and cluster. No gauges at all. Again, it drives great and has no ecu code. Radio, cabin lights, and everything else is fine.

Does anyone know how to test the wiring harness or have access to the manual to share this procedure? We wanted to disconnect the controls to see if the short was there but the other smaller fuses for each accessory are not blowing. This should mean the short is in the main connection in the engine bay correct? Really need the procedure to test the wiring harness.

In the body relay block, (check owners manual for exact location) remove the retained accessory power relay. Does the fuse still blow when you turn the ignition to the accessory position?

Thanks for the advice Captain. My good friend finally had a chance to perform the test you mentioned and it seems we have been able to isolate the short to the steering column wiring harness. At least it does not pop the fuse when that section of the block is unplugged. I was not there so I am just describing what he told me. Will update as I know more.

UGHHH what a nightmare. Still have had no luck figuring out this problem. Any other suggestions is appreciated.

Just wanted to update the thread. The short was finally found. All it took was a little pinch.

just wanted you all too know that i appreciate your thraed , i read this about 10:00 am and looked at my 2001 s10 4x4 same problem except wires were bare where the seal goes into the door.
thank so much for being here and sharing your awesome knowledge !!!!!!!!!