Rear Wiper / Defroster Not Working Simple Fix

[yukondan]

On my '01 Yukon the REAR wiper and Defroster quit working. I found a easy fix after many hours of running various checks.

 

* Checked the fuse

* Checked the relays

* Checked power to the rear Motor and Grid on the window

* Checked for ground

 

All checked OK, But as soon as I turned the switch to the rear wiper on all I got was a CLICKING sound. Thinking it was the motor I removed the motor to see if it was frozen / binding. When I ran a bench test it ran fine........ Put it back in and same thing, Click, Click, Click. When I turned on the rear defoger AND the Wiper at the same time NOTHING not even a click.

 

Now This was telling me not enough Voltage to run both (OR either), So I connected my Test meter to check on a load and voltage was fine. This tells me that there was a bad ground. I checked ground at the start of my testing a had ground. But under load the ground would drop........., SO I started to check for a bad ground using my Helms manual wiring diag. . All easy to get to grounds appear to be fine. Not wanting to start to pull apart the rear head liner, side panels it dawned on me that the easy fix would be.

 

Make a grounding strap from 14 guage stranded wire. Connect the ground strap under the Bolt head for the mounting of the rear wiper motor to the oposite side of the rubber insulator to make a good ground to the rear lift door/body. Problem solved now both the rear wiper and defroster work 100%.

 

The motor assembly of the rear wiper is isloated from the body by rubber mounts to eliminate vibration and sound transmission. Adding a grounding strap maintains the sound isolation but adds a ground right at the most needed location.