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View Full Version : rain sensor has a mind of its own


sp330i
11-21-2003, 08:29 PM
This has happend about 1/2 dozen times from what I can remember. For no reason, the rain sensing wipers will start cycling by themselves without me turning them on by either flipping the lever or adjusting the sensitivity. I leave the lever in the sensor position, but it typically takes flipping the lever on and back or adjusting the sensitivity switch to turn them on. Anyone else experience this phenomenon?

Plaz
11-21-2003, 08:59 PM
Nope. :dunno:

Terry Kennedy
11-21-2003, 10:12 PM
This has happend about 1/2 dozen times from what I can remember. For no reason, the rain sensing wipers will start cycling by themselves without me turning them on by either flipping the lever or adjusting the sensitivity. I leave the lever in the sensor position, but it typically takes flipping the lever on and back or adjusting the sensitivity switch to turn them on. Anyone else experience this phenomenon?I've never seen that, but my guess is that it is most likely to be caused by an intermittent connection in either the wiper switch stalk or the steering wheel slip ring. Neither of those parts is particularly inexpensive (a bit more than $75 each, I think), so your best bet is trying to get the dealer to look at it. With an intermittent fault like this that isn't going to be logged in the computer you're likely to have a tough time of it, though.

e28Will
11-21-2003, 11:25 PM
you also might want to check the glass covering the sensor to make sure that it's clean, because it works off of the coefficient of reflectivity. If it's clean, follow Mr. Kennedy's advice.

Terry Kennedy
11-21-2003, 11:29 PM
you also might want to check the glass covering the sensor to make sure that it's clean, because it works off of the coefficient of reflectivity. If it's clean, follow Mr. Kennedy's advice.Could be. However, per BMW, once the rain sensing wiper has deactivated (due to the car being shut off, etc.) it will stay off until the controls are operated by the driver (either by moving the stalk or by turning the sensitivity knob on the stalk). This is to keep it from going off by itself in a car wash, etc. So I'd suspect it is either something in the controls, in the cables, or in the electronic module that handles things. Most lilkely of the 3 is the controls, since they're mechanical.

sp330i
11-22-2003, 03:19 AM
Could be. However, per BMW, once the rain sensing wiper has deactivated (due to the car being shut off, etc.) it will stay off until the controls are operated by the driver (either by moving the stalk or by turning the sensitivity knob on the stalk). This is to keep it from going off by itself in a car wash, etc. So I'd suspect it is either something in the controls, in the cables, or in the electronic module that handles things. Most lilkely of the 3 is the controls, since they're mechanical.

Thanks for your always insightful feedback Terry. :thumbup:

I should have asked my question more clearly. With their advanced electronics, I know that many BMWs have their share of electrical gremlins. I've also found TSBs that address specific ones with software upgrades or flashes from the MODIC. My real intent here was to discover if others had experienced the problem or if theire were software upgrades to fix.

I agree, given the nature of the problem, the dealer will probably just :dunno: That's what mine seems to do many times. Given the level of service I receive from my local dealership's service department, I'm doubtful that I will buy another BMW.