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73-87 Chevy _ GMC Trucks => Electrical => Topic started by: bedwards on June 15, 2021, 07:37:04 PM

Title: 1985 C10 Windshield washer pump
Post by: bedwards on June 15, 2021, 07:37:04 PM
My washer pump died today. Pump motors not getting 12v. It works on the bench. Checked fuses and wiring. I didn't see a fuse for the pump. The wipers work fine, even the intermittent speeds. What am I missing or has the multi-function switch died? Any easy way to check?

many thanks ahead
Title: Re: 1985 C10 Windshield washer pump
Post by: Captkaos on June 18, 2021, 12:52:58 PM
Have you looked in the wiring diagram section? 
http://forum.73-87chevytrucks.com/smforum/index.php?topic=30115.0 (http://forum.73-87chevytrucks.com/smforum/index.php?topic=30115.0)
Title: Re: 1985 C10 Windshield washer pump
Post by: bedwards on June 18, 2021, 07:52:48 PM
It's been a rough week at work and all I have done is commute in it. Probably will look at it this weekend.
Title: Re: 1985 C10 Windshield washer pump
Post by: bedwards on June 20, 2021, 07:18:49 PM
 Success!!!!
 So the washer as well as all wiper functions go through that POS delay module. I had a hunch as mine has been acting up for a while. It would wipe three times when I start the truck sometimes and then the washer pump quit getting 12v.
    I will try to post pics but basically there is a diode on the module board that fried on mine. It fell apart when I tried to take it off the board. I happened to have one in a box of junk I got from my dad who is a retired EE.

 Many thanks to "bucket" who posted his module and schematic on another forum! https://www.gmsquarebody.com/threads/wiper-pulse-module-15598496.28952/ (https://www.gmsquarebody.com/threads/wiper-pulse-module-15598496.28952/)


The part was a 1N4002. Replaced it and all functions are back.