My windshield wipers stopped working today. When the truck is started, with the wiper switch off, the wipers move on their own every few seconds. They move up about an inch, stay there a few seconds then move back down an inch. They keep doing this as long as the key is on or truck is running. I turned the switch on and it continued to do the same thing moving just a little bit up and down every few seconds. The nuts holding the arms down are tight. The wiper wash sprays fine.
We've had freezing rain all day. And I've had wacky electrical issues in the past with the wiper wash not working and radio display not lighting up. That usually only happens in freezing weather, but it hasn't happened in a while. I have checked the GEM behind the fuse block. I felt all around it as best I could. I've never found any signs of water. Also the GEM has a thin, clear plastic cover over it which I guess is supposed to protect it.
So is it an electrical issue? Or is it the wiper motor? I don't know what to do since they seem like they're trying to work whether the switch is on or off. Any suggestions?

 

It sounds like the wiper 'park' circuit is the only power getting to the motor. That's the circuit that runs the wipers down after the switch is turned off. To me it sounds like there is either a blown fuse or possibly the wiper switch went bad. You will have to test the circuits at the motor to know for sure.

 

You also have the relays under the hood to check as well.

 

I checked the owners manual. There's only one fuse associated with the front wiper/washer and its good. I also notice when I turn the wiper switch on, I can hear a "click" from under the cowl which I guess is the motor. I'll have to wait till tomorrow to get at the motor.

 

Well, I'm stumped. Today they work. I was gonna take the wiper arms off so I could remove the plastic cowl. Before I started, I gave it one more try for the hell of it and they worked. So now what? Should I still take the arms and cowl off and look at the motor? Should I look at the switch on the steering column? Or maybe the GEM more closely? Yesterday the temp was around freezing. Today its a little warmer, somewhere in the 40's. I do remember when I had the issues with the radio and the washer fluid it was in the very cold temps.

 

I had a similar issue when it rained. Although, mine was slightly different. I would turn the wiper switch on and they would work in all speeds in only Park and Neutral. They wouldnt work in Drive or Reverse. I tried everything but for some reason after a few days of everything being dry, they started back working like normal again.

 

Ahh, the infamous windshield leak into the GEM issue.

 

Looks like I'll have to do a more thorough check of the GEM instead of squeezing my hand in there and feeling around. Whats the best way to remove it? Take out the fuse box and whatever else is in the way from the front? And once its out, what do I look for as far as water damage? Thanks for all the help so far?

 

Lots of rain today. My wife just got home and brought me outside to show me a dripping wet spot on the headliner just above the driver's side "a" pillar plastic trim. From the location of the wet spot, I'd say its coming from the moon roof and collecting there. Can't believe neither one of us ever saw that before.

 

I retracted the moon roof. There's a wet spot in the front driver's side corner. I guess its the glass weather seal that's leaking.

 

I snaked some wire down the front drain tube of the sunroof tracks. There was a little bit of crud on the wire when I pulled it out. Then I poured some hot water down the tube to flush it out. Its been about a week and I've been keeping an eye on it. We've had rain but not as heavy as that last round. I'll see what happens.