Blowing the 40 Amp fuse

[Jim L.]

A handy tool is an "automotive short circuit finder." Not very expensive. It injects a tracer tone into a circuit and has a receiver to follow the current path.

The basis of good ideas of others above is that things need to be sensible, indicator lights or audible tones.

Regular battery has too much power for troubleshooting. Better to use a smaller 12v battery or a power supply that is current limited.

 

[N3BP]

Attached is the starting circuit wiring diagram. It appears when the key is turned to the "start" position, it energizes two things: the starter relay and the glow plug controller. I'd be leaning more toward the starter relay and wiring than the glow controller. The glow controller is also energized during the "ON" position of the starter switch, so you would think the fuse would clear then.