Wipers on = wiper fluid sprays. Always.

[Reese Allen]

1980 C20, bought it a couple of years ago. It's had this problem the whole time I've owned it.

Whenever I turn on the windshield wipers, the wiper fluid pump kicks in and starts spraying in regular pulses. And doesn't stop until I turn the wipers off. I can't have one without the other. If the wipers are on, the pump runs and sprays fluid.

Tonight, I replaced the switch (and also installed an AC Delco pulse wiper module) in the hopes of fixing this problem. It didn't. New switch works the same as the old one, even the pulse/intermittent wipe function works, which is awesome, but the problem I was trying to solve remains.

Any ideas? Wires crossed somewhere? I was sure replacing the switch would do the trick. Not sure where to go from here.

[Reese Allen]

I did find this thread after further searching, but it's about a '67-72 truck:

http://67-72chevytrucks.com/vboard/s...d.php?t=424379

No idea how much of the older electrical plan carried over to 1980, but it sounds like the wiper fluid pump's ground wire might not be connected correctly, if my truck is supposed to be wired like VetteVet described in that thread.

[ray_mcavoy]

Originally Posted by Reese Allen

No idea how much of the older electrical plan carried over to 1980, but it sounds like the wiper fluid pump's ground wire might not be connected correctly, if my truck is supposed to be wired like VetteVet described in that thread.

Yes, the wiring remained quite similar. GM changed to a permanent magnet wiper motor with added external connections for the parking switch in 1978. But the control switch is still on the ground side of the circuit.


So if the washer pump control wire is shorted to ground it could keep the pump running whenever the motor is turning. For 1980, the pump control wire should be pink. And a quick way to see if this is the problem is to simply unplug the flat rectangular 2-wire connector from the pump and see if it stops.

If unplugging the connector doesn't make the pump stop, the pump's mechanical engagement mechanism is probably stuck.

[Reese Allen]

Well, here's what I'm looking at under the hood. I don't know which connector goes to what, there's a big black assembly bolted to the firewall with 3 different connectors going into it. It's not clear which connector goes to the pump, or even where the pump is located inside this black thing.

http://imgur.com/LgjGhZL

Uppermost connector has a black wire with a white stripe, and a brown wire.

The next one has a yellow wire and a red wire.

The lowest connector has yellow, brown, and red. The brown wire had a loose wire tap connector hanging from it. There is no other loose wire I can find which might have been connected to the brown wire through the wire tap at some point.

All of these wires lead into the bulkhead thing below which takes them through the firewall along with a handful of other wires coming in from elsewhere.

[Reese Allen]

Further searching turns up this thread with helpful photos:

http://www.truckforum.org/forums/che...op-issues.html

I removed the upper two connectors and the cover from the pump. The cover just pulled right off. It exposed a mechanism that looks just like the photos in the thread linked above. I took a video of it. I'm trying to upload it to youtube now.

The white toothed wheel does not complete a rotation, it just rotates a few degrees back and forth. The arm on the right attached to the spring actuates back and forth and that seems to directly power the pump to do its thing. It seems like it's trying to get the toothed wheel to rotate but that's not happening.

Obviously the lower connector is what drives the wiper motor. Disconnecting the upper two connectors does not stop the pump from actuating whenever the motor is on. So it looks like this is actually a problem with the mechanism, not an electrical problem. Which, as a mechanical engineer, is a bit of a relief because it means I have a better shot at figuring it out. I don't fully understand how the mechanism is supposed to work at this point, though.

[Reese Allen]

Yeah, this appears to be mechanical. After further digging, I find that engaging the wiper washer is supposed to initiate a full revolution of the white toothed wheel. The washer cycle is initiated by a solenoid. The wheel completes most of a revolution and then hangs up at the last or second-to-last tooth, which is the problem. The arm keeps grabbing for it and trying to rotate the wheel to the next tooth to shut the damn thing off, but can't get there. If I force it to complete the loop, the pump stops pumping. I've managed to pull off the white wheel and am now tinkering with it.

[ole dollor]

Originally Posted by Reese Allen

Yeah, this appears to be mechanical. After further digging, I find that engaging the wiper washer is supposed to initiate a full revolution of the white toothed wheel. The washer cycle is initiated by a solenoid. The wheel completes most of a revolution and then hangs up at the last or second-to-last tooth, which is the problem. The arm keeps grabbing for it and trying to rotate the wheel to the next tooth to shut the damn thing off, but can't get there. If I force it to complete the loop, the pump stops pumping. I've managed to pull off the white wheel and am now tinkering with it.

get it where the wipers work , and put an add on washer tank with motor and plumb the hoses to the squrters and put a push button to power the washer when you want it, the best way to fix these old wipers......

[Aus69c20]

Any update on this? Having the same problem on my 69. Had advice it could be a sticky solenoid. Going to have a look this weekend.
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[gmachinz]

Yeah these things are touchy. Its one if the reasons I opted to go with an 87-up fender mounted washer jug and pump.

[Aus69c20]

Update
Checked the original washer motor and the solenoid was fine. Dismantled it and put it back together then reinstalled it. I could hear it working and then turn off but now it wasn't pumping water. In the end I went with something like ole dollar and gmachinz suggestion and attached an electric pump into the bottom of the original reservoir. I wired it back to the original washer conector and pulled off the old pump. Now it works great, is quieter and still looks semi original. Hope this helps.
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[mMad Dawg]

If you look under the gear that rotates you will see that the part that is supposed to rotate the gear is unable to catch the cog and keep on pumping.There is a spring under there that wears and wont allow it to keep turning.I dont think that spring is available to buy. Your only recourse is to buy another wiper motor. Unless you can find someone who rebuilds them.But I think a new one would probably be cheaper. Hope this helps. Gord