Wiper blades on Golf 4 are malfunctioning

Hello!

On my Golf 4 TDI, manufactured in 1998 and with 300,000 km on the odometer, the windshield wipers are developing a strange behavior.

So, if I briefly tap the switch to make it wipe once, it usually wipes ten times, and sometimes the end position is also incorrect.

A friend told me that it's probably due to the motor, specifically that the limit switch contact is faulty.

Yesterday, I took the thing apart, and it doesn't look too bad. I opened the cover for the end-position switch, and it looks quite neat inside as well. I still cleaned the contacts carefully, bent them slightly, and put everything back together. No change.
When the motor (without the wiper arms) is running in interval mode, it stops in the correct end position five times in a row, then twice with a 30° offset (on the motor shaft), and then again five times in the correct position, and so on.
So, nothing has improved.

Does anyone have any ideas?

It's often located on the wiper control module under the steering wheel, on the relay carrier behind the fuse box, on the left side of the door.

Okay, there's water ingress into the connectors in the trunk near the left C-pillar. The contacts are corroding there, which can cause the wipers to malfunction.

If, unexpectedly, you still need a windshield wiper motor, I happen to have a new one here. But your problem sounds very much like the suggestion from the previous speaker!

"On my A3 8L, there were metal shavings near the switch -> try using isopropyl alcohol spray."

Hello!

Thank you for the previous responses!

Here's how things look for me now:

I received a used windshield wiper motor today. I just put it in and tested it, and as expected, it had the same malfunction.
That's not the problem.

Next, I loosened the rubber grommet on the left side of the cable harness where it connects to the roof near the tailgate. I then inspected the cables on that side: it was a complete disaster. The insulation on all the cables was partially peeled off, all in the same spot, which definitely caused a significant disruption in the electrical flow. The copper wires are bare and lying directly against each other.
The rear windshield wiper, however, was still working.
Furthermore, I exposed the electrical components on the C-pillar, and everything looks very good there. The windshield washer hose is also in good condition. Is everything dry?

I then disconnected these 3 connectors in the C-pillar, which made the tailgate (except for the central locking) electrically inactive, and I tested the windshield wipers again.
The malfunctions are still occurring, but less frequently and not as severely as before. It could also be a coincidence, because it has happened before.
It was sometimes worse, and sometimes almost normal.

I couldn't find a new wiper relay today; it won't be available until Monday. I'll try that next.

I'll have to think about how to proceed with the wiring harness on the tailgate. I've already patched it up on the right side before, and that still looks good. However, that was only the three wires for the central locking system.

On Sunday, I'll also take a closer look at the wiper system and see if I can find anything like what Rainer described.

Hello!

Today, I organized the tangled wires at the rear door. I haven't driven it yet, but after some tests, it seems like everything is okay now. I didn't replace or repair anything else; everything else is back to how it was before. Okay, old windshield wiper motor, but the dirt in the water reservoir is now gone .

Did you at least replace the crumb tray? You often get lucky with your VWs and receive ready-made repair kits. There's something similar for BMWs as well, covering all models that have shown issues. However, the quality is crucial: the manufacturer of the repair kit must use sufficiently flexible wires, and the installer must twist the repair kit components together during installation. I will describe it in the last paragraph of my post.

I had to completely rewire the entire cable harness in the rear hatch of the Suzuki Ignis, which I drove until November. To do this, I replaced each individual wire with a color-matched replacement wire. I did it slowly, one wire at a time, to minimize the risk of mistakes. I then routed the connections into a readily accessible corner on both the rear hatch and the body of the car, which required running about 60 cm of cable. In this case, the hose for the rear windshield washer system also had to be replaced.

Generally, in the automotive sector, soldering is avoided during repairs, and instead, sleeves are preferred. However, in the narrow space between the C-pillar trim and the body panel, I wouldn't have had enough room. It would have been possible in the tailgate. There, the individual wires are separated so that when rolling them into a textile anti-noise tape, the solder joints don't end up directly next to each other. On the one hand, there's a risk of chafing, and on the other hand, the cable harness would eventually become uncomfortably thick and, consequently, stiffer than in its original state. The heat shrink tubing provides good insulation, but based on my experience, it doesn't seem to offer much abrasion protection.

When running the wiring into the tailgate, a trick is used that plays a significant role in the later durability of the repair: I would advise against using the textile strap visible in the picture. The rubber grommet, which simultaneously seals the tailgate and the body, is perfectly sufficient as cable protection. The trick now is to get a bit of talcum powder (baby powder) into the cable grommet to prevent future chafing on the grommet and between the individual wires. The best part of this trick is that the individual wires in the area of the cable grommet should not be laid straight, but rather slightly twisted together. Specifically, the entire wiring harness should not be bent when the tailgate is opened and closed, but rather twisted in accordance with the upward movement of the tailgate. Twisting is much gentler on the materials than bending. This is where the aforementioned positive effect of the talc additive comes into play, which allows the individual wires to slide within the cable gland and within the wiring harness. And for precisely this reason, I would not wrap the wiring harness so tightly in this area as it was originally. Even better would be acid-free silicone grease, but then you shouldn't need to access that area so often. It will be extremely frustrating to work on that in the future.

From a design perspective, VW may not have been particularly considerate of material usage at the location shown. The two holes for the cable passage could have been placed further apart. Often, for better cable routing, the holes are positioned precisely in the upper corner of the tailgate. An alternative would have been to move the cable passage further towards the center of the roof on the bodywork side. This would have reduced the twisting. Another approach, used by Ford, was to use spring-loaded contact pins to avoid running a cable harness into the tailgate. Visually, it wasn't very appealing, and it also required some maintenance, but it works even on vehicles that are 20 or 25 years old.

Hi!

Okay, I've done it the "cheap" way for now. I ordered some of those solder-type shrink connectors, and a few meters of new cable.
Putting it all together worked out pretty well.

And yes, I also saw those pre-made repair cable kits, but it was too late to order them, and they would have also cost around ~40 euros.

The car is now 18 years old. I think it will probably last for another 2 years, and then I'll see how things go.

@ Hat Driver:
You're right about what you wrote:
In the past, when I worked in the post office's workshop, it was a real pain with the VW Golfs (specifically the 2-door models), as I constantly had to replace the wiring harnesses. If the tailgate is opened 50 times a day, it's no wonder that something might go wrong.

Back then, we also had Golf 1s, and there were absolutely no problems with that, simply because the cable came out of the body quite in the middle and went into the tailgate on the side. (Or the other way around, it was a long time ago). So, there was enough length to bend it. Then the economist probably thought, "I'll save 5 meters of cable here," and that long rubber cuff certainly wasn't cheap, and what lasts a long time...

I always repair this stuff using leftover cables from Festo sensors that I save. These are highly flexible cables manufactured by Lapp Group in Stuttgart.
"It's likely that there are remnants of cables from other manufacturers available in a similar quality."

Hi!

I've been dealing with this for so long.
It occurred sporadically from time to time.

Lately, things have been bad again.
so that I actually didn't want to drive anymore.
I replaced the windshield wiper relay earlier.

The wiper immediately moved to its end position.
and now it works as it should.
Okay, I've already written that.

I opened up the old relay and found not much inside – just the usual small components, a circuit board, and 2 relays.
However, one of the contacts on a relay was quite burnt, with visible signs of scorching.

I really hope everything is finally okay now.
So, looking back, the first answer from the T3 Surfer was probably correct.

Thank you for the information .