We have ir sd70 roller , 2001 with 4 cy Cummins. We keep blowing fuse for parking brake and safety switches. It kills the machine. We traced harness and everything appears good. What should we be looking for?
Start by finding the park brake valve, it should be under the floorboard. They have a history of going bad. Unplug it at the solenoid and see if your fuse still blows. If not the coil is grounding. If it still blows then there still could be a short in the wiring for the park brake, but I would unplug other safety features (seat switch, etc.....) until the fuse stops blowing. You may go through a few fuses but it will help you narrow down the possible causes and what routes they take through the machine. If you have unplugged everything (do each item one at a time) and the fuse is still blowing, then there is a wire short to ground somewhere.
What is the sn of the machine? It makes a difference. Also when is the fuse blowing? as soon as you install it or during operation? Can you narrow down which function you are using at the time the fuse blows?