Windshield wiper fuse keeps blowing! Help!

[Nick_S]

Out of nowhere a week or two ago the wipers just stopped working on me. Worked perfectly fine early on the day, then nothing. When I got home I replaced the fuse and soon as I turned the key it popped again. Left it sit since I don't drive the car often and avoid rainy days if possible.

Decided to try and dig into it tonight. I had read that disconnecting the harness to the wiper motor and seeing if it still blows a fuse will rule out the wiper motor. However I can't get to the wire harness. I fiddled with a few things, pulled the relay and cleaned all the terminals etc, put a new fuse in...Viola! They work suddenly. Cool I thought, must have been a bad connection on the relay. Put it all back together, take it out for a drive and they don't work again. Tried a new fuse, popped soon as it hit the connectors.

I'm needing the install a new blower motor which since I've got an M50 means pulling the intake manifold off which would also give me access to the wiper motor. I'd like to only do this once but I was curious if anyone has any other suggestions or ways to check for a short before I start buying parts and diving in that would be awesome. Electrical stuff isn't really my strong point.

Thanks!
Nick

[Todd Black 88]

I would replace the relay first. They are notorious for acting up and causing issues.

[AndrewBird]

Sounds like something is shorting somewhere. Check for continuity between the relay contacts and ground. Something might have rubbed through and is shorting against the body somewhere.

[Das Delfin]

Usually a motor at the end of its life will draw more current than it should, blowing the fuse. The hvac blower motor does the same thing. Once you have the blower motor out it's not super hard getting to the wiper motor

[Nick_S]

I'm leaning towards the relay at this point. Just went out this morning, pulled the relay and gave a few taps, reinstalled and it works just fine. Going to try and find a new one and go from there since it's the easiest thing to replace. I'll have to look up how to check for continuity, I have a multi meter but really don't know how to read it or use it, lol.

[Nick_S]

Never mind, definitely not the relay. When I got to work they weren't working already so I tried a few different fuses and even with the relay pulled it's still blowing the fuse. Probably a shorted wire somewhere. Guess I got a project ahead of me trying to find it.

[Das Delfin]

Usually a motor at the end of its life will draw more current than it should, blowing the fuse. The hvac blower motor does the same thing. Once you have the blower motor out it's not super hard getting to the wiper motor

[Nick_S]

Usually a motor at the end of its life will draw more current than it should, blowing the fuse. The hvac blower motor does the same thing. Once you have the blower motor out it's not super hard getting to the wiper motor

Going to try and dig into this Thursday at a friends shop. I'm thinking it's got to be a short somewhere under the fuse box. The fuse gets 12V just fine and will intermittently work just fine. It's usually after a short drive that it will blow them and considering it blows the fuse with the relay not connected would rule out the motor correct? Also that it will blow the fuse when the switch is in the off position.

[Das Delfin]

hmm. When my motor went out, it would only blow the fuse when I turned it on. If yours blows independent of usage, there must be something completing the circuit and leaving the wiper motor out of the loop

unless it also blows when you use your wipers, in which case there could be a short inside the motor itself, as a result of age

However if it still blows with the relay out.. I would grab a wiring diagram and trace the wiper circuit and see if there is any continuity from the fuse to ground to the motor etc that bypasses the relay, to rule that one out. Then if there's nothing, trace the wiring to something you think might age or corrode. Or try to find connections that are easy to get to

Having a wiring diagram is like a treasure map for electrical problems. You can find them on the forum. There's actually an electronic trouble shooting manual for our cars, which has diagrams along with pattern failures and their solutions. You should be able to find it here

[Nick_S]

Correct, it will blow totally unrelated to wiper use. And as of a few days ago, I put in a new fuse and as it sits in my garage they are working just fine so I'm guessing I have a frayed wire or loose connection. My buddy is great with finding electrical gremlins so I'm going to head over there tomorrow.

Thanks for your help!