Automotive Forums

I drive a 1997 GMC Jimmy.  Well, I've had a problem with my windshield wipers for a while now. They seem to work whenever they want to. Sometimes they work, and sometimes they don't. I know I should have fixed it immediately, but last night they decided to stop working on me as I was driving in HARD rain. I ended up running into a ditch. Although there wasn't too much damage, I realize it's very unsafe. The wiper fluid has never worked. Do you guys have any idea of what it could be? I was thinking/hoping it is the windshield wiper motor or something even cheaper. Please let me know any info you have.  

There should be a ground wire going from the windshield wiper motor to somewhere on the vehicle.  Make sure it is grounded correctly before trying to replace the motor.  If there's alot of rust/dirt around where it's grounded, take the ground wire off and clean up around it and put the ground wire back on.  Had the same experience with a GMC Sierra, wipers had a mind of its own, wouldn't work when you wanted them to, and then wouldn't turn off when you didn't want them on no more.  Turned out to be just a bad ground.

Another possiblity is that the harness wiring could be loose/damaged.  Next time it decides not to work, jiggle the harness wire a bit to see if you could get them to turn on.

It's also possible that the switch itself is bad.  But all these should be cheap to fix.  

On that 97 Jimmy the wiper motor comes with a Wiper Motor Pulse Board , part number RAY 49700PB you can pick this board up aftermarket for around $25, I have changed a few for this very problem. It is a circuit board that is installed in the motor housing , and can be changed without buying a motor.