washer pump comes on with wipers every time

[rgunlock]

Working through the little bugs after a 6 year restore of my 78 GMC. One of them is that the washer pump wasn't working but the wipers were. I'd bought a new pump/motor about 6 years ago when I was just thinking to get everything working on the truck - before everything snowballed into a full restore. Not sure the washers worked then, can't even remember if they were plumbed.

Today I just put another new washer/wiper pump/motor on. Good news is that the pump works, but comes on with the wipers without pushing in the switch button. They squirt in low, high, and with the button pushed. I've replaced the switch during the restore, and all the wiring is new - part of an AAW harness I installed.

I could use some help troubleshooting whatever I screwed up. Any ideas? Looking for some "where to start" suggestions before I go pulling my dash apart (again) to start going over the wiring, test the switch, etc.

--thanks, Rick

[ray_mcavoy]

I think temporarily unplugging the 2-wire connector from the washer would be a good place to start.

If the pump continues to operate even with that connector unplugged, you'll know that you are looking for a mechanical issue that is preventing the pump drive mechanism from disengaging.

However, if the pump does stop with that connector unplugged, then you would be looking at an electrical problem that is keeping the solenoid engaged.

[rgunlock]

Thanks Ray. There are two 2-wire connectors going into the pump section and a 3-wire going to the wiper motor. Pulled the 2-wire I'm pretty sure is for the pump. Turned on wipers and it squirted. Pulled the other 2-wire that I believe is the wiper park switch. Turned on wipers and squirt. Only thing left plugged in is the 3-wire connector which I believe just controls low and high speed on the wiper motor.

I assume this means I got a poorly rebuilt motor/pump. Is there any likelihood this is due to bad install or is it possibly an easy fix rather than return or exchange?

[ray_mcavoy]

You're right, the other 2-wire connector is for the park switch. If I remember correctly, the plug for the washer pump is the wider / flatter one. And yes, the 3-wire connector is for the high/low speed operation of the motor.

So it sounds like you're dealing with a mechanical issue that is keeping the pump engaged all the time. I assume you purchased a rebuilt pump/motor assembly that came with the pump already installed on the motor, correct? If so, you could remove the plastic cover from the pump assembly and have a look at the mechanism to see if you can spot anything that was incorrectly assembled when it was rebuilt. The factory service manuals that hatzie posted here --> http://67-72chevytrucks.com/vboard/s...d.php?t=545416 have some good pictures/illustrations in them showing how the washer pump mechanism is supposed to work.

[rgunlock]

Yes, the motor and pump came as a complete assembly. I'll take a look under the cover, but sounds like it will probably be coming off to be exchanged.

Thanks so much for taking the time to respond!