Author Topic: 1985 C10 Windshield washer pump  (Read 1424 times)

Offline bedwards

  • Newbie
  • Posts: 80
  • Newbie
1985 C10 Windshield washer pump
« 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

Offline Captkaos

  • OWNER and Administrator
  • Administrator
  • Senior Member
  • *****
  • Posts: 18351
    • http://www.73-87chevytrucks.com
Re: 1985 C10 Windshield washer pump
« Reply #1 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

Offline bedwards

  • Newbie
  • Posts: 80
  • Newbie
Re: 1985 C10 Windshield washer pump
« Reply #2 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.

Offline bedwards

  • Newbie
  • Posts: 80
  • Newbie
Re: 1985 C10 Windshield washer pump
« Reply #3 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/


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