Windshield wiper issues...

[GunnyGlow]

Programming issue maybe?

At least you know the sensor is functional now.

Sent from my SCH-I545 using Tapatalk

[cn90]

This may be the beginning of wiper motor failure.

[bcredliner]

Since you haven't mentioned otherwise I am assuming when you turn the wiper to constant operation setting they sweep the windows normally. If that is the case my interpretation is that the malfunctions are limited to the rain sensing function and that the wipers don't indexing properly.

If I got that right, the key symptom is the wipers do not index properly. The problem is quite likely the wiper module behind the glove box. I know of no test to confirm that is the problem but one of the key symptoms of a bad wiper module is that the wipers will not index properly. Sometimes when the module is replaced the wipers won't work the first time. If that is the case turn the key off and on several times and they should work.

[DillonInCO]

Indexing? I thought that meant removing the wiper arms and putting them in a different position manually? Do our cars do the indexing automatically somehow? If there is something that controls that and it's gone bad, that would make sense. The wipers actually "park" in different locations, sometimes further up the windshield than others.

Yes, the wipers work as normal in position 2 and 3 (constant speeds).

Wiper module hasn't been replaced in the year that I've owned the X...I think that the wiper module on an E53 is actually the General Module (GM III). That is indeed behind the glovebox. From my research, it is prone to various failures, but mostly windows and locks.

Now that I think about it, about the time this started happening, my X was at an indie shop to troubleshoot window problems. The GM also controls the driver windows. They used an AutoLogic to check the programming somehow; maybe that inadvertently broke the rain sensor. I will probably end up taking it back there to have them look at this, since they're able to troubleshoot a lot better.

[bcredliner]

I didn't make myself clear- I was referencing indexing as the place the wipers should be when they are off, where the wiper arms were initially connected at the bottom of the windshield.

Yes, it is the General module that controls the wiper operation, was thinking of wipers when I wrote it.

The GM controls door locks, interior lighting, seat controls, window controls and the wipers. Are all the other controlled elements working normally?

[DillonInCO]

Ah, that makes sense. Yes, everything else is working. However, pulling the fuse for the rain sensor broke the functionality of the one-touch (automatic down) switches. Maybe related?

For anyone interested, I found what looks like an official BMW document that's extremely helpful. It explains functionality of the ZKE III body electronics system, including the GM, and has an entire section on wipers and the rain sensor. I now believe I have a combination of problems That is to say, I have partial rain sensor functionality and partial standard intermittent (no rain sensor) functionality.

http://www.bmwmotorsports.org/BMW_docs/x5zkeIII.pdf

A few things I noted from it:

- The wiper relay is a double relay. If one stage of the relay fails, the wipers would still function, but be limited. This is apparently a common problem on E38s and E39s, which share the GM III system. I think I'll replace it after all.

- "When the wiper motor park contacts signal the GM of the wiper arm position, the signal is simultaneously sent to the rain sensor as an indication that the windshield has been cleared of water drops and causes the rain sensor to reset the sensitivity delay timer back to 0." With my wipers swiping twice, this means that something is probably wrong with the wiper motor park contacts, or at least the signal output by them. That means replacing the wiper motor.

- Vehicles equipped with a rain sensor do NOT use the vehicle speed to control wiper speed. Only the standard (manual) intermittent function uses this. Yet my X clearly uses the vehicle speed to change wiper speed.

- When there's a fault in the rain sensor circuit, the wipers revert back to standard (manual) intermittent function, controlled by the knurled rotary dial on the stalk. Yet, I don't have standard intermittent functionality, as the rotary dial does nothing.

[DillonInCO]

Oh, I just saw something else in that PDF, on page 15. It's a table explaining what happens when there's a fault in the wiper system. The first line is this:

Behavior: Intermittent Wipe
Problem: Short or open circuit of the knurled wheel signal
Solution: Delay value for setting 3 used.

That's it!! That's what my X is doing. Intermittent wipe, stuck on setting 3. So worst case scenario, this could be possible:

1) Fault with the rain sensor is causing Position 1 to revert back to standard intermittent behavior when it's not raining, or lightly raining.

2) Fault in the turn signal stalk means the rotary dial doesn't work and is stuck on setting 3.

3) Park sensor contacts on the wiper motor are bad. Wiper motor needs to be replaced.

Best case scenario it's the relay I also found this old archived forum post which suggest that taking apart the wiper motor and re-greasing it will fix the park position.

[bcredliner]

Didn't think about the relay, oopsie. Sometimes it is just corrosion, so you might be able to spray it clean or even just unplug it and plug it back in.