# 87 GMC 1500 P/UP Wiper Issues



## detailman (Jan 27, 2004)

I have a 1987 GMC 1500 P/up with the wiper switch on the turn signal with delay wipers. When I was plowing the wipers were working fine and all of a sudden they stopped right before they stopped the motor started making a noise so I replaced the motor with the new motor they worked for about 5 mins and now they wont come back on again. I also noticed that if I wiggled the whole motor assembly around when I was installing it it would work once or twice when I put it all back together it was working perfect but didnt last long. I was wondering if it could be the turn signal switch is there a short somewhere? or should I look at other things first. Everything has power going to it. I dont want to keep buying things that dont fix it. Thanks for any help.


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## toptech72 (Oct 7, 2008)

Check and make sure you have a good ground at the wiper motor.


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## MickiRig1 (Dec 5, 2003)

Have the wipers been acting funny for a while? They will have random wipes when not on. The delay will stop the wiper in mid swipe? That can be a sign the control box is going. Or the multifunction switch has a problem.( stalk ) That noise you heard may of been the control box frying. You may have a control box under the dash or it may be in the motor assembly. Get the box at a junk yard, dealer will rape you $100.
Like the above post make sure the ground is clean and dielectric grease is put all over it.
Clean the entire hold down bolt till it's shiny. The ground usually has a metal grommet around the mounting hole with a wire leading into the motor. Make sure the wire is connected. look at all the wires too. Make sure they are not breaking off ect. Might even run a ground wire right to the motor.
There should be a test procedure in the repair manual for the wiper circuit.


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## detailman (Jan 27, 2004)

Excellent Thank You very much I will start with that. Where is that control box I see a couple of things under there. Micki the delay would act funny. Thanks


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## MickiRig1 (Dec 5, 2003)

We go to Virgina Beach for vacation every year. I love your state, we have drove all over checking it out.


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## sweetk30 (Sep 3, 2006)

www.ck5.com for good info on 73-87 trucks of gm style. hope this helps. i a not much for electrical but thay are good site and info.


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## detailman (Jan 27, 2004)

Could you tell me where that control box is? I have checked everything else. On to that idea now. Thanks


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## MickiRig1 (Dec 5, 2003)

Look in the repair manual and see if it notes a separate control module for the delay function. Like Ford they change stuff for the lowest bidder. The repair manual should tell you. It's worth the $25 to buy one. If it has one it will be attached under the dash somewhere. Or it's part of the wiper motor. It just depends what the repair manual says and if Chevy feels you can repair it.


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## B&B (Nov 4, 2006)

detailman;933932 said:


> Could you tell me where that control box is? I have checked everything else. On to that idea now. Thanks


It's clipped to the steering column right behind the metal trim panel below the column. Just remove the platci trim first and then the metal one and you'll see it. It's about the size of a cigarette pack and will have an aluminum finned heat sink covering one complete side.

To test the wipers without the delay module simply disconnect the two connector plugs from it and plug them together, just as in a truck that wasn't delay equipped. If the wipers now work you've found the issue. Although I can't ever recall the delay module causing the wipers to not work at all. Usually you just lose the delay positions.


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## detailman (Jan 27, 2004)

Well after making it only a short time trying to fix them because its 20 degrees and 30mph winds here is what I found this time. Now there is no power to the motor there was before. The module is good and fuse is good. have power to fuse and module but none to motor. Probably has nothing to do with it but now something is draining the battery every night as well. Could this be the switch on the signal problem or a short in the wiring expecting snow at the end of the week and I have to figure this out. Thanks for all the help you guys have been great.


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## detailman (Jan 27, 2004)

also no power to wire harness at motor when its disconnected from motor either.


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## B&B (Nov 4, 2006)

You stated you have power at the delay module but on which side...in or out? Did you bypass the module to eliminate it as an issue?


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## detailman (Jan 27, 2004)

Power at both sides and yes by passed it still nothing.


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## B&B (Nov 4, 2006)

When you're checking at the motor for 12V which wire are you checking? If memory serves me correctly there's a hot wire thats constant hot with the ignition on and it leads from the wiper fuse directly to the motor. It doesn't go through the wiper switch or module.


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