Wipers and sprayer pump

Tiny
JUSTIN GRAY
  • MEMBER
  • 1997 GMC YUKON
  • 185,000 MILES
Wipers and spray do not work. They did work at one point but both do not now. Tapping on the motor did get them going sometimes but not anymore. I replaced the wiper pulse board and that did not fix it. The fuse is fine. Would a bad wiper motor affect the spray? The switch is on the same arm as blinkers and my blinkers work.
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Sunday, April 30th, 2017 AT 9:19 AM

10 Replies

Tiny
CARADIODOC
  • EXPERT
Start by measuring the voltage on the wiper motor. Specifically, put your meter's negative probe on the battery's negative post or on the engine or body, then put the positive probe right on the motor's metal housing. If you find any voltage there, you need to add a ground wire. The motor is bolted to a metal plate that is mounted on vibration-isolating rubber bushings. One of them has a ground strap, but that can arc away near the mounting bolt and cause a broken connection.
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Monday, May 1st, 2017 AT 3:27 PM
Tiny
JUSTIN GRAY
  • MEMBER
So found out my wipers work only if the plug is barely plugged in on one side?
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Monday, May 1st, 2017 AT 5:44 PM
Tiny
JUSTIN GRAY
  • MEMBER
All the right 12v to wires so grounding problem? Would a new motor assembly fix this?
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Monday, May 1st, 2017 AT 6:34 PM
Tiny
CARADIODOC
  • EXPERT
Did you check for voltage on the motor housing? If you do find it there, that only proves the motor is good, and replacing it won't solve the problem. The ground strap is where the grounding problem originates. That is on the motor's mounting plate. The fix for this is to attach a new ground wire between the mounting plate and the body.
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Monday, May 1st, 2017 AT 9:13 PM
Tiny
JUSTIN GRAY
  • MEMBER
It read like 00.01 in a couple places. If I take the motor off would I see the ground wire? There are 5 wires going to the plug, I thought one of those would be ground
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Monday, May 1st, 2017 AT 9:14 PM
Tiny
CARADIODOC
  • EXPERT
In case it wasn't obvious, I should have mentioned the wiper switch needs to be in the "low" or "high" position so voltage is being fed to the motor. You should have 12 volts on the purple wire when in the "high" position, and 12 volts on the yellow wire any time the ignition switch is on. If that is when you found 0 volts on the motor housing, the ground wire is not the problem. There is a thermal circuit breaker in the motor that could be defective. They cause more problems than they prevent, due to arced contacts.
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Monday, May 1st, 2017 AT 9:47 PM
Tiny
JUSTIN GRAY
  • MEMBER
Something is deff wrong internally. I took the black housing off the motor and in certain positions, the wipers worked but if I screwed it on it didn't. Something to do with the black cases position relative to the magnets make it work for some reason. I'm just going to get a new motor assembly
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Monday, May 1st, 2017 AT 10:02 PM
Tiny
CARADIODOC
  • EXPERT
Keep me updated on your progress.
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Monday, May 1st, 2017 AT 10:39 PM
Tiny
JUSTIN GRAY
  • MEMBER
So progress is I got a new motor assembly and it worked. Sprayer work as well. Something was shorting on the inside of the motor where the magnets were. I just hope I got the drive arm on tight enough ha ha
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Tuesday, May 2nd, 2017 AT 9:15 PM
Tiny
CARADIODOC
  • EXPERT
Dandy. The engineers found the need to add a pile of electronics to the motor assembly. In the past we had a washer switch that, when pressed, forced the wiper switch to turn on mechanically. Now they turn the wiper motor on electronically when the washer switch is pressed. They found a solution where there was no problem, and added a lot of unreliability in the process.

Happy to hear you solved it.
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Wednesday, May 3rd, 2017 AT 12:23 PM

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