Peterbilt Power Issue

I have a 2002 Peterbilt 379. Truck will start and run with no problem. I have no power to the ACC side of the truck. I have not heat, wipers, power mirror, ect. Anyone have any ideas as to why or where to look. I have checked the fuses under the dash. I am lost and could use some help. Thank you.

 

The Main Accessory Relay in the dash is where I'd start. It's on the left side usually above the fuse panel in the key switch area. It is a large 75 amp relay, part # 16-03405. Key accessory power activates it to power up all the accessory fuses.

 

First couple of places I'd look are inside the battery box and behind the ignition switch. Look for wires that have come off or disconnected. Any fuses or relays you find should be checked. Also check where the harness plugs into the ECM and the back side of the fuse box.

I wish I could point you to a more specific place but this is kinda strange that NOTHING is working. Tells me it's gotta be a major wire or a harness plug or something.

 

Grape Ape knows his business. Check that relay.

 

Take out the far left dash panel and the relay is in there, there are 2 in there back to back. Small one closed with the key and energize the big one that power all the acc.

You can change it, just hard to reach, probably loose a little skin but that is where you problem is

 

Super reply.....

 

Ok found the big relay. Used a jumper wire and got everything to work but my cab heater

 

Hope it is a big wire, keep the fire extinguisher handy

 

Yes it was a big wire just used it to test the relay. Got the new relay in and everything seems to work

 

How much skin did you scrape off?