C3: Windshield Washer Problem

[Matthew S.]

I have a 72 Vette that I recently bought and the windshield washer doesn't work when you push the washer button. I took the washer cover off and by manually moving the mechanism inside the washer I was able to get it to pump water every time. So I now know that the washer will pump water and that the pumping mechanism and lines are fine. The problem is that the small coil that is supposed to engage the pumping mechanism isn't working. I took the washer pump off the car and examined it and I found that the wire around the coil had burned off of one of the terminals. I unwrapped the wire once, reattached it to the terminal and put the washer pump back in the car. I started the car and pressed the washer button and I saw the wire turn bright red and burn out again. I checked the wires running to this coil (the two wires that connect at the top of the washer pump through the cover) and one of them has power whenever the ignition is on. Is this correct? Should the coil be energized all the time or is there something else going on with the washer circuit?

Is it possible that the coil is just worn out and needs to be replaced? I bought a new washer pump but don't want to put it in until I'm certain it's not going to get ruined in 5 seconds.

Thanks for any advice.

Matt

[Joe C.]

Re: C3: Windshield Washer Problem

Matt:

The coil should be energized momentarily, when the "washer" button is pressed. This solenoid (coil and plunger) will engage the washer pawl for about five revolutions of the planetary gear in the wiper transmission. This causes the washer bellows to cycle for those five revolutions.

If the solenoid wire "glows red" then it is shorted, probably because of a "holiday" in the insulating shellac.

I am not sure whether these windings are reproduced, or not. Next best thing would be to cannibalize another wiper motor assembly.

I have successfully rewound some of these spools. It involves unravelling the wire completely and hanging. Recoating the wire, and rewinding.

Joe

[Matthew S.]

Re: C3: Windshield Washer Problem

Thanks Joe,

So if I understand how this should work, the wire that connects to the coil should NOT be energized all the time. It should only be energized for a moment when the washer button is pressed. That makes sense to me and would indicate that I have a problem with the switch or some other component in the circuit.

Matt

[Joe C.]

Re: C3: Windshield Washer Problem

Mike:

Believe that the switch completes the ground leg. Test by applying momentary 12 V across the 2 WSW pump leads.

Joe