Windshield Washer Help - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**JAZ72C10** · 03-09-2026, 01:59 PM

Installed a new original reproduction washer pump from Classic Parts. I tested it before I put the dash back together and the washer squirts fluid on the windshield continuously. It only stops when I shut the wipers off completely. Is the on off switch itself bad? OR is it the new pump? I disconnected the power to the pump itself and it continued to pump washer fluid. The pump also seems to be leaking where the piston enters the pump chamber. Did I just get a bad unit?
1972 c10

71meangreenc10 · 03-09-2026, 04:49 PM

If it is leaking, that is not good. The switch itself only provides the ground circuit for the pump and washer. There are two sets of plugs on the washer/wiper unit as you found. If your switch is loose on the dash it can make things quirky. What I do and some others have done and is an easy modification is to install a S10 blazer washer reservoir in the old bottle location and call it a day. I make a harness to connect into the old washer plug so it uses the switch like the factory style. I also make new washer lines to delete them from inside the cab. If something goes wrong, quick trip to the parts store and put in another pump. Easy peasy...

Here is my thread from 2016:
https://67-72chevytrucks.com/vboard/...d.php?t=714339

Smitty

03-09-2026, 01:59 PM	#1
JAZ72C10 New Member Join Date: Jan 2026 Location: Northeast Ohio Posts: 9	Windshield Washer Help Installed a new original reproduction washer pump from Classic Parts. I tested it before I put the dash back together and the washer squirts fluid on the windshield continuously. It only stops when I shut the wipers off completely. Is the on off switch itself bad? OR is it the new pump? I disconnected the power to the pump itself and it continued to pump washer fluid. The pump also seems to be leaking where the piston enters the pump chamber. Did I just get a bad unit? 1972 c10 Last edited by JAZ72C10; 03-09-2026 at 04:04 PM.

03-09-2026, 04:49 PM	#2
71meangreenc10 Its a Truck Thing...... Join Date: Dec 2004 Location: Sierra Vista, Arizona Posts: 3,261	Re: Windshield Washer Help If it is leaking, that is not good. The switch itself only provides the ground circuit for the pump and washer. There are two sets of plugs on the washer/wiper unit as you found. If your switch is loose on the dash it can make things quirky. What I do and some others have done and is an easy modification is to install a S10 blazer washer reservoir in the old bottle location and call it a day. I make a harness to connect into the old washer plug so it uses the switch like the factory style. I also make new washer lines to delete them from inside the cab. If something goes wrong, quick trip to the parts store and put in another pump. Easy peasy... Here is my thread from 2016: https://67-72chevytrucks.com/vboard/...d.php?t=714339 Smitty __________________ 71 C10 283/3SPD Full Resto 70 C10 Suburban Former military GSA truck. 72 Chevy Blazer 4X4, Sloppy Jo, Mountain Climber. Wife says no more trucks. http://67-72chevytrucks.com/vboard/s...d.php?t=707378 72 GMC 1 Ton Motor Home, wife said no more trucks until she saw this one. Gen 3 6.0/4L80E 4.10 http://67-72chevytrucks.com/vboard/s...d.php?t=761110 68 GMC Suburban was 3/4 ton, now 1/2.Wife shook her head 71 C30 Wrecker 71 C20 Scott-Bilt As weird as it gets..BB Cheyenne AC Truck 68 GMC Long Stepside. They keep following me https://67-72chevytrucks.com/vboard/...d.php?t=841215 69 C30 Former Motor Home, Flat Bed time 70 G20 Red-E-Kamp Conversion "I'm your Boogy Van" Last edited by 71meangreenc10; 03-09-2026 at 04:58 PM.



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