Zirconocene

I've been having an issue with my windshield wipers that I can't quite seem to track down, so I hope that someone can tell me what else I need to test or validate to get them working again. I'll start with some history, then go into what I've tested.

At the start of the rainy season here the wipers were working on all settings (intermittent, low, med, high; I don't remember testing the momentary setting). One day, the wipers just stopped moving on the windshield, not in the park position. Having read a bit about deterioration of the bearing in the motor, and general corrosion issues, @Michael Benno came over to help me rebuild the system and get things working again. We removed the entire assembly (motor and linkage) and set about freshening things up. While Mike cleaned and lubed the linkage, I opened up the motor and saw a nearly pristine example. It was genuinely like new in there. There looked to be some grease on the contact tracks but even the grease was still greasy, and not cakey. So I cleaned up the tracks to remove some of the grease, put the removed grease back on the worm gear and buttoned everything up. When we reinstalled everything the wipers worked as expected. The belief was that there was some binding that was making the wipers fail.

A week or so later, driving home in the rain, the same thing happened again, where the wipers just stopped near the top of their arc. Here comes the troubleshooting and investigation, in mostly chronological order.

- Motor removed and bench tested with a separate power supply. When grounding either through pin 6, or the pigtail attached to the motor housing, 12V applied to pins 2, 3, or 5 activate the motor.
- With the key in the ignition set to ACC, testing for voltage at the control harness indicated that there was power at pins 2, 3, and 5, but also 4. Pin 4 had power regardless of stalk position. As I read the wiring diagram, this is how it is supposed to work, so I don't think this is an issue but please correct me if I'm wrong.

Connecting the motor harness to the stalk harness did not activate the wipers. Retesting the motor on the bench still showed that the motor moves when 12V is applied. This indicated to me that there was in issue with the pins and sockets in the 6 way OEM connector. I'm not a fan of those anyway, so I swapped it over to a Deutsch 6 pin connector. Testing the motor in the same way as before, a bench power supply made it move the way it's supposed to move. Testing the stalk harness with the new Deutsch connector also showed power at the correct pins after changing that side of the connection. Connecting things up, still no movement on the wipers.

It was suggested that the intensive washer relay (#9) might be mucking things up, so I removed that, inspected the fuse again, took out the intermittent wiper relay (#11), and then lost all power to the stalk harness side of the connection. The original wiper relay (#11) was original to the car, or at least it has a 1989 build date stamped on it, so I ordered a replacement VW part that is recommended as an upgrade to set the interval. Installing that still provided no power to the stalk harness connection.

At this point, it seemed to me that the problem may lie in the switch itself but, before taking that out, I ran the following tests:

- With the ignition set to ACC, I see power to the top of fuse 34. I tested with with the fuse in place via a grounded test light, not with a multimeter, so I don't know the voltage (this may be a problem).
- With the ignition off completely, I checked for continuity between the bottom of fuse 34 (with the fuse in place, so maybe that's a problem) and the sockets for the washer and wiper relays. Each relay shows continuity to a different socket (don't remember which at the moment).
- With the ignition off completely, I tested for continuity between the bottom of fuse 34 (fuse in place) and L24. This test showed continuity to that pin.

This made me think I had a problem at the stalk. Since I needed to fix the turn signal function anyway, that was my next step. I'll update this thread after my next batch of meetings.

Any thoughts in the mean time would be appreciated.

Thanks

Zirconocene

Part II, loving the opportunity to really dig into electrical gremlins. /s

Thinking that the problem was in the switch I removed the steering wheel and stalk assembly. The good news (genuinely) was that my turn signal stalk was broken and not working correctly, so I was able to fix that (I think, but so far so good. That's a topic for a separate post). The contacts on the wiper stalk looked a little oxidized, and there was some grease on them, so I went through, cleaned off the grease, took off some oxidation on the surface with light sanding, and finally put some DeOxit on them to clean off any residual crud. Reassembly was relatively straightforward and the little clips from Garage deLoods were very helpful to keep things in place prior to reattaching the metal cover plate. Once reassembled, I tested the following for continuity:

- Continuity between pin 53a and 53 exists at the low speed wiper stalk setting.
- Continuity between pin 53a and xx exists at the medium speed wiper stalk setting.
- Continuity between pin 53a and yy exists at the high speed wiper stalk setting.
- Continuity between pin 53a and J exists at the interval wiper speed stalk setting.

After reinstalling the steering wheel the following was observed:

- The headlights popped up and were on as soon as I reconnected power. Turning the light switch on an off did nothing. It was only after I pulled the light stalk back to turn on the brights momentarily that the light **** started acting correctly. However, I now only get brights when I pull the stalk, and there is no change when I push the stalk forward. It almost seems like there's a learning that gets done at power up and my light stalk may have been pushed forward when I reconnected the power so maybe another power cycle will get that reset appropriately.
- I still don't get any power to the connector from the stalk harness on any pin, at any wiper stalk setting.

So with all that, any ideas about what to do next for the troubleshooting? It feels a little bit like the next step is much more intrusive so I'd like some ideas before I go further. No matter what, I'm going to go back and re-run some of these tests and see what I may have missed.

Any help would be greatly appreciated.

Thanks

copperstew

I had a similar issue with my wipers, but since it was intermittent I put up with it until one day my turn signal stalk failed to return to center.

I bought a used one from 928intl. I installed it. All problems went away.

My wipers now work correctly all the time (in my case it was the switch in the stalk that was doing it).

Idea: Since you have two 928s, swap the stalks.

Mrmerlin

replace the turn signal switch

Zirconocene

@Mrmerlin and @copperstew : OK, I'll contact Mark and see what's available.

Cheers

Michael Benno

Hey Glen, there are a few different versions of the combination switch and they vary by year, options, and language. You are looking for a 90-91 switch with english. Here is an excerpt from PET. It would be wise to have @Mark Anderson provide guidance on which one you need.

PS, I am worried you have not updated your signature file yet.... Keeping secrets I see.

Mark Anderson

We do have this one unit but the cruise was removed. You con easily move yours over 964-613-332-00 which supersedes to 01 $150

Zirconocene

@Mark Anderson : Sounds good to me, I'll take it. You still have my payment info, right?

Thanks

Mark Anderson

i do and shipping tomorrow

Zirconocene

Thanks for jumping in Mark, this saves me a lot of hemming and hawing about trying to fix the part on my car. This needs to work sooner rather than later so it's good to cut to the chase.

Cheers

Mrmerlin

NOTE prior to installing the new used switch I suggest to spray D100 into it as its a lot easier to do off the car

Zirconocene

Solved!

Thank you thank you thank you thank you thank you to the inestimable @Michael Benno for his time, experience, and general level of fitness and flexibility.

After running some more continuity tests it really seemed like the issue was in getting power to the stalk cluster. At that point, there was really only one more thing to do and that was to pull the CEB and see what was happening.

Here was the issue:


Ugh

Two major things that needed addressing:
A#1: the oxidation. Lots of cleaning with DeOxit and some small copper brushes I made with leftover electrical wire.
B#2: The contact/blade receptacle things are really spread apart.

I don't have any after pictures but while things don't look pristine, they are much cleaner, DeOxited, and the dang prongs have been smushed together to make proper contact with the fuse.

One more thing that needs addressing is figuring out where the heck the water is coming from that caused that oxidation but that's a problem for a future @Zirconocene .

Cheers and thanks to all for the help and insight.

Michael Benno

It was fun to figure out this mystery. Hopefully we have it solved, and a bonus we were able to correct the improper harness routing in the CE panel area. Next step is to remove that rats nest of aftermarket wires for the remote start / lock. Sorry for breaking that for you. Judging by the corrosion throughout the top of the CE panel and fuse holders, I suspect that will be coming out for a more thorough cleaning when this 928 is not your daily driver. Too bad you don't have any before pictures, it was scary. Happy to help you out.