Tech Tips (by ALLDATA): Isuzu NPR-HD blows 80-amp fuse

TECH TIPS (courtesy of ALLDATA)

Vehicle: 2002 Isuzu NPR-HD, L4-4.8L DSL Turbo (4HE1)

Mileage: 226,005

Problem: No electrical power was available in the vehicle. The battery was fully charged.

Details: The technician found that the 80-amp FL-1 fuse was blown. He installed a new fuse, which blew immediately, even with the key in the Off position.

Based on the wiring diagram, the Tech-Assist consultant suggested unplugging the alternator because it was one of the main components connected to the GL-1 fuse circuit. Other circuits had their own smaller fuses, which should have failed if there was a problem in their circuits (see diagram).techtips-isuzu.png

Confirmed Repair: The technician unplugged the alternator and the fuse was okay. The alternator was replaced and the vehicle was fixed.