Wiper Fuse Blows As soon As Key is Turned On

[kenz5380]

My Wiper fuse blows every time I turn on the truck whether the wipers are on or not. I've traced the wiring and do not see any obvious shorts. Before I start buying and replacing parts does anyone know of a common place where this circuit shorts out with age? There has been no modification to this part of my wiring and I haven't changed anything in my electrical system in a long time before this went bad so I have no reason to believe the issue comes from something I did. I've toyed with the idea of replacing my fuse block as I have heard they are a common source of shorts. Has anyone done this or do you all have any thoughts about it?

Thanks for the info in advance.

 

[Anubis8472]

I would start by unplugging the wiper motor.
If the fuse no longer blows then the problem is in the motor and not the wiring to it.
Course if you have a meter simply check for proper readings at the plug. (continuity to ground on the power side would be bad)
It could be a short inside the motor.
Basically you want to start there and work towards the fuse.

Not certain, but I think the washer pump is in the same unit?
Also check TM's and see if that circuit feeds anything else.

 

[MarcusOReallyus]

What he said.


Tracing visually is a good first step, but now it's time to get the meter out and see what you really have.

 

[kenz5380]

Not the motor, fuse blows when it is disconnected. I'll get out the meter next time I have some time and daylight. Thank you for the suggestions, keep them coming.

 

[Anubis8472]

Scouring through the TM's I couldn't find the diagram for the wipers.....
Turns out I was missing a TM.

The diagram for the wiper motor circuit is in the -20 ,appendix F , F-22 (I think that's Page F-22, Figure F-20 ... you'll find it)

It looks like you only have one wire (white) supplying power from the fuse to the motor assembly.
The rest of the wiring is all ground side control.
So if it's still blowing with that unplugged the problem has to be between that plug and the fuse block.
The wire is taped together with the others so unwrap them and make sure it's not shorting to the other wires.

Bad news is that's a short wire that should be simple to find any problem there. Meaning it's likely in/around the firewall conector-fuse block.
Good news is, if you can't nail it down you should be able to bypass it with a simple key-on 12v feed. (fused of course)

 

[byrnestree]

my wiper only works on slow...idk why but this just recently happened. any clues as to whats going on? hate electronics

 

[MarcusOReallyus]

That's a separate problem. It needs a separate thread.