95 SC2 wipers only partially work

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Charles G.

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Windshield wipers don’t work on regular or any of the intermittent settings, but work normally on high speed, when the windshield sprayer is activated, and single wipe. Any ideas what the problem is?

Thanks!
 
Is it 100. 00% reproducible in the ways it works and the ways it does not work? Also, did it progressively lose functionality or did this happen all at once?

The different switch setting positions in the wiper stalk are supposed to select the different speeds, but all of the electronics and programming for the wiper module is stored in the wiper arm transmission that sits under the cowl on the exterior bottom of the windshield.

Logically, low speed and low speed intermittent settings are all based on low speed. If the electronics or programming get damaged, it makes sense that all four of those would go out. What doesn't make sense is that low speed still works for windshield washing and single wipe. Then again none of this makes any sense.

I have a 95 SC2 factory service manual. I'll take a look at the wiring diagrams tomorrow. When mine went fubar, I replaced the wiper transmission unit and all was fine.
 
So far as I can tell it is indeed reproducible, though I had only just tried all of the intermittent settings individually yesterday (previous it was simply on 2 when I had tested the problem). It does appear to have happened abruptly, but it is hard to tell when - this is sort of a back up car that is only rarely driven.
 
Could just be dirty contacts in the switch on the stalk.
Rotated briskly from off to the highest setting, making sure you feel the contacts on the moving part brushing up against the contacts on the stationary part. The idea is to remove a thin layer of corrosion that may have formed on the not often used positions, which tend to be the intermittent settings. It's called sweeping the contacts. Don't go crazy speed wise as things may not touch the way they are supposed to, and after all these years, some of the contacts may have fatigued and bent back a little. Don't spray anything in there for the time being.

Someone just revived their hazard switch doing the above. You can go back and forth Just One setting if you wish. I'd say to probably do this for 3 minutes at a time with the engine and the key in the off position. You don't need to freak out the control module or drain your battery. Then put it in accessory mode where all the lights on the dash light up but you haven't cranked the engine. Test it in that setting. You may find you get some of the functionality back and not all of it, but this is the most likely way to get the functionality back if you can get one to come back, it should eventually work for the others. My wiper module went bad at 235k. The wipers would start on their own occasionally and simply wouldn't turn off when I turn them off. High speed always worked. So first we go after the contacts on the stalk. If that doesn't work, we'll talk
 
I can try it a little more, but going back and forth did not produce any appreciable effect.

BTW it was me with the hazard switch :-)
 
I'm trying to make sense of the circuit diagram on charm.li, but it is rather complex at first glance. It looks like the stalk just makes connections to put different resistances in the circuit in order to change the speed / interval of the intermittent settings. I'm trying to figure out how hi speed can work but low speed does not. It will likely come down to a wiper transmission replacement as described above. Simply put, I don't like to spend other people's money unless I'm pretty damn sure. And I'm not quite there yet on this
 
I'm torn on this one.
I've seen explanations that point in both directions. The schematic clearly shows the different resistors being located in the stalk itself. However there is a microprocessor on the wiper motor control board that is mounted in front of the windshield outside the car.

In order to properly diagnose this, you need access to determine if the circuits on the stalk are continuous.

If that passes, then it pretty much indicts the control module by the motor.

I've not ever seen a post on the Saturn forums I have been on where anyone has determined the stalk to be the issue. And after 30 years, it's not unreasonable to consider a new wiper transmission assembly. They are a bit of a pain to change in terms of getting them in and out, but with a little sheet metal bending anything is possible.

If I can find a diagnosis tree in the field service manuals, I'll try to post it in the next few days.
 
One other detail that I noticed a couple weeks ago: when I engage the windshield sprayer the intermittent settings suddenly work more or less normally. The normal speed setting does not, however. And if I turn off the wipers, the intermittent won't work unless I engage the sprayer setting. Don't know if that gives anymore insight, but I thought it odd enough to be worth reporting.
 
Do you mean intermittent settings work in the rain after you wash the windshield until you turn the wipers to off?
 
Derf said:
Do you mean intermittent settings work in the rain after you wash the windshield until you turn the wipers to off?
Click to expand...
Doesn't have to be in the rain as such, though I noticed this by accident in the first rainstorm of the SoCal season recently. But yes, if I wash the windshield and then flip to intermittent setting they will work - sometimes inconsistently or a bit of "herky jerky" (likely from prolonged disuse) but they will work.
 
Since is not consistent and the movement is not smooth, I recommend replacing the wiper transmission. If nothing else, it's 30 years old and has been out in the sun, rain, snow, hail, twisters, etc. They all seem to break in a different way but it is all due to the microprocessor on the transmission itself. It may not be consistent, it may function by doing sequences that should not be necessary, but at the end of the day, it should just be replaced. We can run in circles trying to sort out the diagram for the goofy operation, but if the issue lies in the microprocessor going bad, we will never find it that way. Again, I would just replace the wiper transmission. Especially well the remanufactured ones are still available
 
It comes as an integrated unit with the circuit board installed inside to control the motor. Watch online a few videos because it is next to impossible to remove and install without ending a bit of sheet metal. Which is no big deal, it's just a frustrating experience. I wanted to take the unit I removed from my vehicle and wail on the engineer who thought it was okay to install it through that slot. You'll see what I mean. It only comes out one way and it only goes in one way. Enjoy
 
Apologies, my memory sucks.

You need a new motor because the circuit board is attached to the motor and it's the only way you can get the circuit board. You do need to remove the entire assembly, then take out the motor and switch it with the new one, paying attention to the alignment. Then putting the whole unit back in. If the wiper posts themselves do not move smoothly, just get another transmission, because I only see one on Amazon and it is a total no name. Anything you find used will be at least 25 years old and likely not better than yours.

Again apologies
 
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