175 AMP Glow Plug Intake Air Mega Fuse.
If your glow plugs or intake air heater is not working on your Duramax engine, one of the problems could be a blown fuse.
For 2001, 2002, 2003, 2004 GM 6.6L Duramax LB7

Replacement 175 AMP Mega fuse

If your glow plugs or intake air heater is not working on your Duramax engine, one of the problems could be a blown fuse. This fuse protects the main power circuit to the glow plugs/IAH.Fuse is mounted under the plastic fuse panel cover in the underhood fuse block mounted on the drivers side fender

Application:2500HD 3500 Silverado Sierra 6.6L V8 Duramax diesel:2001, 2002, 2003, 2004 early