Rear wiper blows fuse, why?

[2Paths924]

The 10 amp fuse for my rear wiper blows every time I activate the switch. Already replaced the switch and it still occurs. The mirrors work perfectly without any issue, but try the wipers and the fuse is toast. Any suggestions on where to look and how to fix this issue? 

Thanks in advance. 

[Frenchy]

If the fuse popped then you have a short in that circuit. Could be a wire or wiper motor 

[Slartibartfast]

Hopefully it's just the motor. Remove the plastic cover inside of the rear hatch, unplug the motor, and see if the wiper switch still pops the fuse. If it doesn't, then it's probably the motor, though I would test the motor before replacing it on the off chance unplugging it just broke the circuit to some other faulty component.

 

If the fuse pops without the motor, or the motor tests good, you'll have to do some digging. EL-69 of the '90 manual (free download from cardiagn.com) shows the whole circuit. EL-90 has component locations, EL-93 and up should help you find the relevant connectors. By disconnecting those, you can narrow down where the problem is. If the fuse doesn't pop anymore with 13B disconnected, then you know the problem is in the hatch. If it still pops with 297M disconnected, you know the problem is between 297M and the dashboard. You could unplug the amp and/or relay. IIRC they're behind the lower trim, left of the rear cargo area. If unplugging one saves the fuse, either that component or something downstream is bad. This approach should narrow stuff down so you're not screwing around chasing wires at the wrong end of the truck.

 

If you can't be arsed to do all that, or your troubleshooting leads you to the rear hatch harness, check the wiring between the body and the hatch. That's the only place in the circuit where wires have to flex, so that's where I would expect the wiring to fall apart first.

[adamzan]

What Slart said. And to be honest I would start at the hatch. Check the wiring at the rubber where it flexes, common issue on most hatchbacks.

[2Paths924]

Thanks for all the help. I have a replacement motor and after I plugged it in the fuse blew. So on to the hatch wires and relays. 

[Frenchy]

Is it going to be quite simple. First unplug your wiper motor. Go to activate it and see if it pops a fuse. If it does follow the harness and go to the next plug. Unplug it. Try to activate the rear wiper and see if it pops a fuse. If it does not you at least eliminated a lot of work of where it could be and now you know where you need to look. Of where it could be and now you know where you need to look.