Wiper diagnosis

[Obwonkonobe]

It rained for the first time in an eternity here in Arizona yesterday, and i figured I'd give my wipers a try. The KINDA worked, but they were struggling hard. They would crawl accross the windsheild, no matter what position the switch was in. I haven't trouble shooted anything yet, but my guess is a dying motor. If anyone knows how to bypass the switch and try to trip the motor, or how to test the switch that'd be great, also if anyone could actualy explain how the switch works, like the modes amd speeds etc, thanks

78 c10, pretty standard deal

 

[1987 GMC Jimmy]

I don’t have any wiring schematics or troubleshooting diagrams, but I can almost guarantee that the motor’s at fault here. I’m not usually one for shotgun diagnoses, but if the linkage isn’t rusted or binding, it’s gotta be the motor. @chengny would have the technical information. I have noticed something with my Jimmy, though. That thing has sat a lot since 2004, and I only started using it as a backup daily last year. The wipers hadn’t been used much either, and when I first started using them, they were stupid slow. It didn’t take many rainy days, though, and they got fast to where they’re just as good as any new car. They’ve stayed fast, too. My hypothesis there is the grease that they pack in the motor is getting hard while sitting. I don’t know if that has anything to do with it, but it’s a thought.

 

[Snoots]

Search this site for schematics and test tips. We can help best if you post a picture of your w/w motor and is it controlled by the stalk or a switch on the dash?

 

[Charlie]

I recommend disconnecting connector and reconnecting on switch in dash and also on motor on firewall first. Could be bad or corroded connection. I had issues with mine and that was all it was which was a relief.

 

[Obwonkonobe]

I've got a switch on the dash, 3 positions including when it's off, and you can push it in, for what im guessing is a shot of fluid. Il try giving it straight 12 volts when i get the chance but the grease sounds interesting too. Anyone know how the linkage can be accessed to be lubricated? Also don't worry about my pointing to the cruise transducer bracket in the pic

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[1987 GMC Jimmy]

You’ve gotta pull the wiper arms and cowl to get to all the linkage. One thing I’ve never been able to master is pulling those arms off the shaft. Did you disconnect your washer lines from the pump?

 

[Obwonkonobe]

You’ve gotta pull the wiper arms and cowl to get to all the linkage. One thing I’ve never been able to master is pulling those arms off the shaft. Did you disconnect your washer lines from the pump?

Yea the po had the tank out and all the lines off. Ive just never gotten around to putting new lines in and making a new tank

 

[1987 GMC Jimmy]

If someone shares how to get those arms off, I’ll be happy. I need to touch up some paint, and that’s the main spot. Plus, I’d like to have the option of switching to cowl wiper nozzles.

 

[Obwonkonobe]

If someone shares how to get those arms off, I’ll be happy. I need to touch up some paint, and that’s the main spot. Plus, I’d like to have the option of switching to cowl wiper nozzles.

Ive had them off, I think you just pull up on a little tab, then pry them up. Its on a spooned know, pretty easy the senond time around

 

[1987 GMC Jimmy]

I haven’t tried in a couple years. I had all the instructions memorized at one point and just couldn’t get them to budge. But thanks. Talking about it tempts me to want to play with it again.

 

[Obwonkonobe]

I haven’t tried in a couple years. I had all the instructions memorized at one point and just couldn’t get them to budge. But thanks. Talking about it tempts me to want to play with it again.

Hit it with some penetrant in the morning and forget about them for a couple more years lol

 

[chengny]

It rained for the first time in an eternity here in Arizona yesterday, and i figured I'd give my wipers a try. The KINDA worked, but they were struggling hard. They would crawl accross the windsheild, no matter what position the switch was in. I haven't trouble shooted anything yet, but my guess is a dying motor. If anyone knows how to bypass the switch and try to trip the motor, or how to test the switch that'd be great, also if anyone could actualy explain how the switch works, like the modes amd speeds etc, thanks

78 c10, pretty standard deal

Diagnosing slow wipers is an inexact process and these tests can be done in any order - just do what is easiest first (or go right to what your gut tells you is the problem). What you are trying to determine is whether they are slow because of:

1. A mechanical problem - specifically in the transmission. Really rare and usually associated with badly damaged or disconnected linkage. You'd know if this was the case - there'd be a lot of banging and clanking going on under the cowling. There are only 3 pivot points and the pins ride in hard nylon bushings - they don't require lubrication

2. An internal motor problem that would cause slow speed or low torque.

3. An electrical problem with the control circuit (e.g. in the wiring, switch or ground connection)


To check for a weak motor, flip the wiper arms back - or remove them from their splined pivot shafts (drive spindles). Run the wipers and note whether there is any change in speed. If they operate at normal speed with the wiper blades clear of the glass...you might have an extremely weak motor. It's not even strong enough to sweep the rubber blades across the glass. But don't condemn the motor right away, it may be fine and the problem is with the control circuit

So, the next thing to check is whether it will run at normal speed with the control circuit by-passed. This means that you will supply the common brush directly with battery voltage and each of the LO/HI speed brushes with a good path to ground (one at a time).

In this diagnostic image they refer to the common brush terminal as Power - Motor. Get two good quality test jumpers (or make them up yourself). Ignition switch OFF and wiper switch OFF. Pull all 3 connectors from their sockets. That's the washer pump (2 wire), park switch (2 wire) and wiper motor (3 wire).

To test LO speed operation... you know, I am sick of typing and it sounds like you know what you're doing. So, here is the diagnostic diagram for test LO/HI speed only - to avoid confusion I eliminated the wash and park terminals:

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If the motor doesn't run at normal speed - with direct battery voltage and a good solid ground path - pull it and run the test again. If it still is slow, either get a new one or replace the brushes.

 

[Obwonkonobe]

Diagnosing slow wipers is an inexact process and these tests can be done in any order - just do what is easiest first (or go right to what your gut tells you is the problem). What you are trying to determine is whether they are slow because of:

1. A mechanical problem - specifically in the transmission. Really rare and usually associated with badly damaged or disconnected linkage. You'd know if this was the case - there'd be a lot of banging and clanking going on under the cowling. There are only 3 pivot points and the pins ride in hard nylon bushings - they don't require lubrication

2. An internal motor problem that would cause slow speed or low torque.

3. An electrical problem with the control circuit (e.g. in the wiring, switch or ground connection)


To check for a weak motor, flip the wiper arms back - or remove them from their splined pivot shafts (drive spindles). Run the wipers and note whether there is any change in speed. If they operate at normal speed with the wiper blades clear of the glass...you might have an extremely weak motor. It's not even strong enough to sweep the rubber blades across the glass. But don't condemn the motor right away, it may be fine and the problem is with the control circuit

So, the next thing to check is whether it will run at normal speed with the control circuit by-passed. This means that you will supply the common brush directly with battery voltage and each of the LO/HI speed brushes with a good path to ground (one at a time).

In this diagnostic image they refer to the common brush terminal as Power - Motor. Get two good quality test jumpers (or make them up yourself). Ignition switch OFF and wiper switch OFF. Pull all 3 connectors from their sockets. That's the washer pump (2 wire), park switch (2 wire) and wiper motor (3 wire).

To test LO speed operation... you know, I am sick of typing and it sounds like you know what you're doing. So, here is the diagnostic diagram for test LO/HI speed only - to avoid confusion I eliminated the wash and park terminals:

You must be registered for see images attach

If the motor doesn't run at normal speed - with direct battery voltage and a good solid ground path - pull it and run the test again. If it still is slow, either get a new one or replace the brushes.

Thanks that helps a ton, just the diagnostic I was looking for, il try it soon

 

[Rusty Nail]

Omg it rained in Arizona?
Global warming pwnn!
We are all dooooomed!!

 

[Snoots]

Omg it rained in Arizona?
Global warming pwnn!
We are all dooooomed!!

Could've been a heavy fog.

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