'88-'90? How to remove wiper pulse module from wiper motor?

[deckeda]

(The '91? - later trucks have a different design.)

I found an image that provides a hint.

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I can maybe kinda sorta reach that screw underneath. But I can't turn it. Certainly can't see it. And without knowing if it's phillips, Torx, hex head, whatever, I don't want to waste time messing it up.

Guessing its a phillips but I can't get actual leverage on it. The screwdriver sorta engages with it, sorta doesn't.

Does anyone know? Thanks.

 

[WILWAXU]

I don't remember what it was exactly, but I recommend replacing the whole thing with a '92 and newer setup.

 

[deckeda]

Thanks John. Yeah I may be headed that way, mostly because the values of the resisters and electrolytic capacitors in the original setup have likely drifted over time ... even if I did fix the cold solder joints that are probably causing the wipers to be flaky.

I suppose if I was really interested in seeing if this could be fixed, I could just remove the entire motor assembly, THEN with proper access take the module out, and if that didn't fix it I'd already be partly ready for the replacement motor and wiper module if I leave the cowl area off and wiper arms off while testing.

 

[WILWAXU]

Thanks John. Yeah I may be headed that way, mostly because the values of the resisters and electrolytic capacitors in the original setup have likely drifted over time ... even if I did fix the cold solder joints that are probably causing the wipers to be flaky.

I suppose if I was really interested in seeing if this could be fixed, I could just remove the entire motor assembly, THEN with proper access take the module out, and if that didn't fix it I'd already be partly ready for the replacement motor and wiper module if I leave the cowl area off and wiper arms off while testing.

I went through the same thing, ended up with a new '92+ one from Autozone. If you want to do it for cheaper, grab one from your local pick-a-part and add a new pulse board. Never heard of a motor going out.

 

[deckeda]

Picked up one from a '93 today from my local salvage. It'll be a day or so before I can swap it in. The wiper pulse board it came with looks "OK" but I may try to safely blob a little more solder on those harness connections.

The motor has some thick red dielectric lube still in it so I suppose it's alright, and the interior behind the board was clean.

I watched one video about motor removal where their truck's wiper motor had a dual ball setup on the motor arm. This one came with a single ball. Hopefully I can swap the arm from mine if I need to.

 

[someotherguy]

Just re-solder the joints where the socket attaches to the board and install it. It's a wiper motor.. maybe the 'net has caused us to overthink these things.

The 88-90 motor can be re-soldered too but as you've found it is a little trickier to get it apart. It's been a long time since I did one but IIRC it's a torx screw, probably a T20, and then the plastic cap over the board has tabs that have to be carefully released; of course the plastic is brittle by now so you have to be careful.

Richard

 

[deckeda]

Thanks Richard, when I remove it I'll probably still attempt to fix it and hang onto it since there are two other trucks in the stable that could use it. Like I said, since I'd have to remove the whole thing to successfully disconnect the two pieces, the truck's getting a newer design motor and board. Maybe I'll first see if I can really get a T20 in there first, though.

This junkyard wiper board's not original. The cover's been ripped off previously but there's enough of the plastic tabs remaining to secure it again.

I reflowed most all of the joints on the bottom of the "new" board (obviously I didn't touch the surface mount components.) There's a ground trace that looked bad/cut/burned for a little rectangular component that's sort of in the middle of the board.

I wasn't 100% sure it was supposed to go to the ground trace that rings the board, but it sure looked like it should. I went online, looking for pictures of this 2nd gen board to confirm. Guess what? There are several different designs out there, with different circuit paths and component locations! Like maybe the industry took a look at the GM board and decided, "Hey let's not get sued. Let's redesign it." (Just a guess.)

I was able to blob some extra solder to bridge the tiny gap, but if it doesn't work I can solder in a short wire over to one of the ground locations on the board. I'll check that "new" trace for continuity tomorrow.

 

[someotherguy]

I've seen original GM pulse boards with a single burnt trace as well; it's easily repairable with a small jumper wire. When the solder joints fail on the harness socket, the one closest to the edge tends to fail first as it's closest to where all the flexing takes place; and that's the ground. When you lose ground, the current tries to find ground through another path...that tiny little trace isn't enough to support the current and burns up.

I *think* you can get the 88-90 motor's board out without removing the motor. It's just not obvious until you've dug into one. Again it's been years but I seem to recall it was right in between "easy" and "difficult"..

Richard

 

[deckeda]

It's all removed now and yes I see the Torx bolt. It's going on the shelf for now.

What I like about the newer design is that if the board (or what I've done to it ... ) gives me any trouble I can just swap it out easily with readily-available replacements and without any acrobatics involved.

I lost one of the two brackets down in the yard that secures the passenger side arm to the motor. Why it has two brackets spooned together I do not know. Now I'll need to move the truck out of the way and sort through al the leaves. Ugh.

Meantime, I can bolt the new one in and see if it works before reattaching the wiper arms.

 

[someotherguy]

Well, there's the actual bracket which the nuts clamp down onto, and the piece underneath it acts as a bearing.

Richard