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Old 12-11-2018, 02:08 AM   #1
fredscarryall
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Wipers freaking out

My wipers in my 1990 454 ss are freaking out. One day last month i was working on my truck. When I was done I went inside. About 4 hours later I walked by my garage and I a heard a strange noise. I open my garage and my wipers were going. The switch was turned on but my keys were in my pocket. Turning the switch a bunch of times, I finally got it to shut off. I then disconnected the battery. The next day I connect the battery back up and the wipers and the washer pump started running. Again with my keys in my pocket. No matter how I turned the switch neither the wipers or washer pump would shut off. So I unplugged the connector going to wiper motor pulse board.I replaced the turn signal lever,the combination switch, ignition switch and the turn signal switch. Pluged it back in and it still wouldn’t shut off both no matter how I turned the lever. I then replaced the the wiper motor and pulse board with the newer style motor and pulse board ( with the c style pulse board ) because they no longer make the old style pulse board for the straight style boards. I then plugged in the new wiper motor and same thing. No mater how I turn the lever the washer pump and wiper keep running with no key in the ignition. So I unplugged it again. But now the rain has started and I need my wipers. Anyone ever have this problem or have an idea how to fix it. Another strange thing is ever since I bought my truck the power windows can go up and down without the key in the ignition. But for that, it only works when I push the window switch up and down. I looked under my dash and see no strange wires and everything looks factory. Here are pics of what I replaced so far.
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Last edited by fredscarryall; 12-11-2018 at 02:37 AM.
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Old 12-11-2018, 10:27 AM   #2
4x4k30
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Re: Wipers freaking out

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Last edited by 4x4k30; 12-11-2018 at 10:38 AM.
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Old 12-11-2018, 11:41 AM   #3
speedygonzales
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Assume power is going to the motor at all times

A motor like any load has to have power to run. It must be getting power to it from another source. Your job is to find that source.

Luckily my son works for a shop and has access to Mitchel so I got the diagrams for both 2 speed and intermittent.

Not sure which you have but it looks like based on the photo of the wiper control, you have intermittent.
Shown here:
http://s1371.photobucket.com/user/St...tml?sort=3&o=0

NOTE I think the drawing is mis labeled on the low line. It should be the orange wire NOT the grey wire. The grey wire is out to the pump. I feel the low line is the orange wire and this one is the one to focus on.

The motor is going to have a 5 pin connector going to it. One pin is ground. One other pin connects to the washer pump. One pin brings 12 volts directly from a fuse. This pin will be hot as soon as the key comes on. The last 2 remaining pins are hot only when the wiper switch is in either High only or on low or intermittent.

So if your wipers are running on low (when they should be off). Then the high speed switched wire is going to be off when your wipers are running all the time.

First question, when your wipers are running when they are not supposed to be, are they running at normal speed or hi speed?

With power off (battery disconnected if you have to), disconnect the connector at the wiper motor and confirm the ground wire is connected to ground. The black wire. Ohm it ground and confirm it gives you the same reading on the meter as when you short the leads together.

Now keep the connector off the wiper motor and reapply power (connect the battery if you have to).

Measure the voltage on the purple wire. It should be low or 0. Now for the problem child, the orange wire. Check it see if it has 12V.

I believe the orange wire will have 12 volts all the time. Let us know what you find and we will go from there.
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