Intermittent rear wiper problem 08 Yukon

[alstonsailor]

Thank you.

 

[Doubeleive]

I’m having problems understanding how the wiper will work at all if the motor is bad.

it's not just a motor it also has a control module

 

[alstonsailor]

Where is the module? Is it a relay?

 

[Doubeleive]

this is why I said it would be easier to test the motor first just to rule it out, lol

Rear Wiper Motor Circuit Test
1. Ignition OFF, disconnect the harness connector at the rear window wiper motor.
2. Test for less than 1.0 ohm between the ground circuit terminal D and ground.
 If greater than the specified range, test the ground circuit for an open/high resistance.
3. Verify that a test lamp illuminates between the B+ circuit terminal E and ground.
 If the test lamp does not illuminate, test the B+ circuit for an open/high resistance or short to
ground.
4. Ignition ON, test for B+ at the signal circuit terminal A while the rear window wiper switch is in the
delay and on switch positions.
 If B+ is not present, test the signal circuit for an open/high resistance or short to ground. If the
circuit tests normal replace the turn signal multifunction switch.
5. If all circuits test normal replace the rear window wiper motor.
Component Testing
Rear Window Wiper Switch
1. Ignition OFF, disconnect the X4 harness connector at the turn signal multifunction switch.
2. Rear wiper switch OFF, test for infinite resistance between the ignition terminal 1 and the signal terminal
2.
 If not the specified value, replace the turn signal multifunction switch.
3. Rear wiper switch in the ON position, test for 900-1.5K ohms between the ignition terminal 1 and the
signal terminal 2.
If not within the specified range, replace the turn signal multifunction switch.
4. With the rear wiper switch in the DELAY position, test for 2000-2400 ohms between the ignition
terminal 1 and the signal terminal 2.
 If not within the specified range, replace the turn signal multifunction switch.

 

[Doubeleive]

Where is the module? Is it a relay?

I believe the module is part of the rear motor assembly

also just a side note, if your vehicle is "rain sense" equipped the issue you are having could be related because the wiper will only wipe once unless rain is detected, so to test that if you have rain sense pour water over the front window view rear mirror area which is where the rain sense sensor is located and see if the wiper activates like it should.

 

[wjburken]

I was not aware that the rain sensing function had any impact on the rear wiper. Thought it only controlled the windshield.

 

[alstonsailor]

I just have to figure out which part is telling it to not keep going.

 

[Doubeleive]

I was not aware that the rain sensing function had any impact on the rear wiper. Thought it only controlled the windshield.

it might not control the rear wiper but it would be easy to find out by just running a water hose over the front window, and that may only apply if the wipers were in delay mode

 

[wjburken]

it might not control the rear wiper but it would be easy to find out by just running a water hose over the front window

Very true. Wasn’t discounting your troubleshooting methods. Thought I learned something about my last vehicles that I didn’t know about.

Continue with your course on troubleshooting.

 

[Doubeleive]

Very true. Wasn’t discounting your troubleshooting methods. Thought I learned something about my last vehicles that I didn’t know about.

Continue with your course on troubleshooting.

it was just a Note in the service manual, but looks like it would only apply if the wipers were in delay mode