electrical problems on a 379

Discussion in 'Peterbilt Forum' started by pulling my hair out, Jan 7, 2013.

  1. pulling my hair out

    pulling my hair out Bobtail Member

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    We have a 1994 379 that's kickin' my butt. Electrical short somewhere on wire #298, main feed to everything. Can't even start the truck without jumping around it. Schematic available is the size of a postage stamp and nearly impossible to read. Pulled all relays and fuses and can't isolate it. HELP!
     
  2. RJC

    RJC Bobtail Member

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    When you open the schmetic for what you want at the top is a place to click to enlarge the page. Just tried it and it works good.

    Wire 298 shows to come off the relay that is in the frame rail by the starter. It runs into the truck to the dash. It connects to the acc. relay. That is located behind the middle dash panel/ Relay may be bad.
     
  3. truckmechanic

    truckmechanic Medium Load Member

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    94 should be behind the far left panel with the storage pocket better pull the wire through and inspect it good you will have to pull the lower steering.colum panel and unbolt the fuse box and pull it out some the wire tees off behind the fuse box also check the back of the fuse box the brackers are notorious for corroding and failing due to leaking windshields.the bracker on the frame rail gets its power strait from the starter