wiper issues on 88 sub

[xpndbl3]

I went out and bought a new wiper module that goes under the steering column as suggested on this board for my 88 3/4 ton suburban. The wiper switch has also been changed to a known working one since I swapped out columns a while back. The wipers only work on one speed setting for a while then stop and you have to re-adjust the speed setting and it'll start back up. Also you can hold the mist setting until the wiper makes 1 full movement then release the button then the wipers will stop wherever they are. I was told it was a bad module so it was replaced. Looks like a heat sink under the column. What now could be the issue?

 

[readymix]

stop cam atached to the motor housing in the engine compartment.

Pull it out and clean the electrical contacts.

Mine does the same thing.

 

[xpndbl3]

would this be the contacts that the wires go into? Or are you talking about taking apart the wiper motor assembly and cleaning in there?

 

[readymix]

On mine the switch just comes of the motor housing. Two wires going into it near the top on the front side.

Mine did have a wierd plastic shroud/dust cover over it. Geting that off was the hardest part.

 

[xpndbl3]

alright thanks, i'll give it a shot when the sun comes back up, burb is too big for the garage door

 

[xpndbl3]

the cover came off easily, but I didn't see any switch inside that I could swap out. Tomorrow if it's not raining I"m going to swap in the whole assembly out of my 91 suburban that I junked that the wipers worked well to see if that solves it. Then I can get a pic of what it looks like with the cover off to see if it could be pointed out better for me.

 

[romeolimagolf]

The wiper motor is not actually touching the firewall. There are rubber bushings on the bolts where the wiper motors are attached to the firewall. On one of the mounting bolts, there is a ground strap that grounds the motor to the firewall. If this strap is heavily corroded or broke, the wipers may behave eratically. My wipers on my '94 Z71 was doing the same thing. I ran a new ground wire and it fixed the problem.

 

[xpndbl3]

I don't believe I have a ground strap on my wipers at all. Nor do I remember one off my 91 sub either. I'll just alligator clip a ground tomorrow initially before swapping out motors. thanks for the tip.

 

[romeolimagolf]

You are right. I just checked my 1986 Blazer it does not have a grounding strap either. That is kind of suprising. I had this same problem on my '94 Chevy Z71, my dad's '92 Chevy Z71, and my Aunt's Astro van. All were fixed by running a new ground wire. I just assumed all Chevy wiper motors were mounted like that. That is what I get for assuming.

 

[xpndbl3]

well it's been rain ALL day, so I'll push it back til tomorrow after I finish moving or saturday. I don't see a spot for a ground wire, but I'll try it first. Never know it might work.

 

[73k5blazer]

The motor housing needs grounded, as well as the module. There's a black wire coming off the module that runs to ground as well.

Consult this post w/diagram

 

[xpndbl3]

swapped in the complete wiper motor assembly from my 91 suburban that I junked and now the wipers work beautifully. Can anyone explain how to disassemble the one out of my 88 sub and attempt to fix it to keep as a spare?