Hey all, I have done everything I can think of to fix this. I started with the RR WPR fuses in the Underhood block and the Instrument Panel block, replaced the wiper pulse board on the front wipers, then replaced the rear motor itself. Nothing has worked to get this thing to move. I have searched high and low to find any additional information but nothing else comes up. Anyone have any miracles working with the rear wiper? The washer pump works and squirts, just the blade does not turn on at all.

Thanks,
Darren

 

The rotary switch itself could be bad - push (for washer spray) and rotate (for the wiping) are two different functions of the switch. Same rear wiper switch is used on a lot of the full size GM SUV's as well (some will also have a fog light button) and are cheap on eBay.

Could also just open the switch up and try cleaning its contacts but it is a bit fiddly to get into it. I've had a few apart to swap bulbs and/or upgrade the bulb to LED in the switches.

Could also just be a pin in one of the connectors backed out of the connector.

I'd start first back at the motor itself though and test with a meter to see if you are even getting power to the connector. If yes, bad motor. If not then back to the switch and other areas to figure out why power is not getting to it.

 

Ah I forgot to mention, I also replaced the entire switch. I will tear things apart again and check to make sure all of the connectors are all the way seated and have power.

I was afraid that would be about the only thing left other than a bad (new) motor. I was really hoping there was an unnamed fuse or something, but I will keep working on it.

Thanks Mix!

 

I have still not been able to figure this out. I have removed the wiper motor and bench tested and it functions correctly. I have tested the plug at the rear and everything seems good. Does anyone have a wiring diagram for the rear wiper to follow all the way back to the switch or any experience with fixing this issue? This is so frustrating!

 

you checked for power at the motor i am assuming but did you also check the ground? many times they get overlooked but are just as important.

 

See the attached..... apparently there is an actual rear wiper control module on the liftgate but the attached are all of the GM service docs specific to the rear wiper.

 

MixManSC great info, very useful.

I also found various bits of info which may help.

If there is GND on B and 12V on A and D gets pulled upto 12V when the dash-switch is in LOW, then it's the module.

So it could be the controller, I read there was a recall on it apparently it lets in water, but never seen one personally.

The module is , fairly cheap from Amazon (circa $42) , quite small.




Some sellers incorrectly identify it as windshield pulse board.

 

You guys are the best! Thats exactly what i was looking for. The controll was replaced when i replaced the motor itself, but i will check the board inside and make sure its clean and no corrosion or anything. Thanks again guys!

 

coffeydp

did you have any luck?

 

Hey Ocean, yeah I tore the whole thing apart, and it ended up being the 12+ that ran from the fuse box to the rear was corroded and broken. I had to trace the wire from the rear lift gate plug all the way to the engine bay testing along to find the problem. Right after the pillar between the driver and passenger doors was a sention of the wire that had been replaced with what looked like speaker wire, and it had corroded all the way through, and seems when I tested it the first time it was barely hanging on. I cut the ****ty patch job out and put in some new correct wiring. After that all was working like new! I have no clue why the section of wire was replaced, nothing looked to be added/removed from the area and the taping looked to be factory still. If you are having trouble, I would check continuity on the wires if you cant find any other reason. It takes a little time to tear the panels off and trace the wiring, but that was the only thing i had left to do.