Pulse / Delay / Intermittent Windshield Wipers

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Schurkey

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I'm borrowing a friends '89 K1500 extended cab while my '88 is down with a popped engine. Part of my "rent" is that I get to fix about a thousand things that are broken or non-functional on this vehicle.

Today's successful project was to get the windshield wipers functioning reliably. The wipers haven't been reliable for months. This became a priority as yesterday it POURED ALL FRIGGIN' DAY and Rain-X wasn't handling it.

The wipers would work...sometimes. They might work for several miles then quit, they might not work for miles--or days--then start up again. There was no pattern, and twisting/pulling/wiggling the Multi-Function Stalk did nothing productive. When I started work on this thing, the wipers were totally dead--no pulse, no low speed, no high speed.

I disconnected the 5-wire molded plug from the motor under the hood, and stuffed a test light into each of the five connections in the molded wire harness end that plugs into the wiper motor. I had some power, I had some ground. I plugged the connector back in, and pushed 'n' pulled on it a little. The wipers would work as long as I applied pressure. I took a wild guess, and bought a wiper circuit board. About $30.
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In one place, it says "Remanufactured". In another, it says "New". I think the thing is new, not reman--But I don't know for sure. I really hate "Made In China". But what am I gonna do?




Well, I pulled the three Torx-head screws that hold the cover on. They also hold the circuit board "in". The board pulls right out other than some friction from the three connections at the lower left in the photo below.
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The grease inside was hard. I added some fresh onto the worm gear at the very bottom. The grease you see in this photo is original.

On a whim, I grabbed a magnifying glass, and looked at the solder joints on the original circuit board. The first ones I looked at were the six solder joints nearest the harness connector. (lower, right side in photo below.)

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There's one that is covered in Conformall, a moisture/weather barrier--the red blob near the "Pulse" molded-plastic harness connector. It's the same red crap on the left side of the board. I could see--with the magnifying glass--that the solder joints were broken on three of the six connections close to the harness connector, next to the red blob.

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Three minutes with a soldering iron, some rosin flux, and two inches of thin-gauge solder. Six joints re-flowed. I did a quick inspection of the other joints that didn't have the red Conformall on them and they seemed OK. I left 'em alone.

There are two "arms" that make contact with the big, round disc in the motor housing. They're on the back-side of the circuit board, and I don't have a photo of them. One was covered in hardened grease. I cleaned 'em both, and I bent them "up" for more pressure on the disc.

I slapped it back into place, put the screws into the cover and tightened. Snapped the wire harness into place.




POW! Wipers work just like they should. Every time. Pulse, low-speed, high-speed.

Fixed.

All that's left is to return the Chinese circuit board to NAPA for a refund.
 
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Eveready

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Nice work Schurkey, NAPA might object to your copyright notice on pic of their box but nice work anyway. That is likely to help someone else with that problem. It has been described before but Photobucket likely crapped on the pictures.
 

Schurkey

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NAPA might object to your copyright notice on pic of their box but nice work anyway.
No problem. I'm copyrighting the photo, not the box.

There's several devices I've fixed by re-flowing solder. For example, I had to re-solder the heater control board on my '88 when I bought it, and again about five years later.
 

someotherguy

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Nice work...welcome to about 1998 or so. ;) A quick search would have shown you the cracked solder joint fix and avoided the trip to the parts house.

Some still believe the new circuit board is the preferred fix, but I'd rather repair an original any day. Easy, quick, and free.

Richard
 

jaywestfall

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Good picture and write up. I just replaced mine with a new AC Delco a couple of months ago on my 1998 C1500. I think that one was made in Mexico...
 

Z Fury

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I've been told soldering is pretty simple to do/learn, but I'm too tired of dealing with this issue. I'll pick up a new board and install this weekend, and will attempt to fix the old board after I teach myself how to solder.

Excellent write-up Schurkey. This should make my install process go pretty simple.
 

Schurkey

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In this case, a fourth-grader could do it with some guidance from an experienced person. You wouldn't be trying to solder it "fresh" or trying to attach a component by soldering, you're merely re-flowing it, adding a touch of flux and the tiniest bit of additional solder.

The tougher part is staring at it with the magnifying glass, looking for the cracks that indicate a bad solder joint. From the sound of things, a person would re-flow those five joints and be done with it. (Leaving the one with the Conformal coating alone unless you see a problem with it.)
 

Z Fury

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I ended up swapping out my board two weeks ago, and now the rains have stopped coming. I may have to get my Camaro out and wash it to resummon the storms...

Swapping it was very simple though. I kept the old one so I can fix it another day. I ended up buying an AC Delco one through AutoZone. Cost a bit more than the others and was still made in China, but I'm hopeful it is a bit closer to OEM spec.
 
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