XSeries-forum

Anyone know where I can find the rain sensors on BMW scanner 1.4.0 they work fine in the day but not when it's dark

Don't know about the scanner but I do know they work by bouncing light through the inside of the screen glass. If this light is interrupted by rain drops scattering the beam the sensor registers rain and sets of the wipers. I would make sure the screen is spotlessly clean in that area with no chips.

And the glue bond to the glass must be perfectly clear too. Are your auto lights being affected too?

Not tried auto lights.

[quote=""dirtymonkey29""]Anyone know where I can find the rain sensors on BMW scanner 1.4.0 they work fine in the day but not when it's dark[/quote]

i don't believe its in the scanner... can't remember seeing it

Will have to have a good look, lights don't seem to be affected

Seems odd that it works in daylight, but not at night. Have you tried running water down the screen to see if you can trigger it.? I assume you hae tried the various sensitivity settings on the wiper stalk?

The actual sensor is replaceable as it clips into a bonded mount on the screen, but it does not sound as if that is the problem. If it had been the other way around I would have suspected either a dead/dying IR emitter or receiver LED.

Have you had any work done on the screen, or know if the screen or sensor have been replaced. In either case, the system needs re-initialising but this seems to be a dealer function. It's referred to in the TIS as needing the BMW Diagnostic system connecting to resolve. Specifically to DIS & Modic being needed.

No idea if any work has been done previous to me owning but I would assume it has been. I too it back when I bought it as the rain sensors didn't work at all and it was re-coded by an independent specialist in leeds

That sounds like a potential source of the issue then - coding not properly done? Has it been like this since that was done?

Had auto lights on today and when it rains the headlights come on. Would have though it would have put side lights on only during the day

[quote=""dirtymonkey29""]Had auto lights on today and when it rains the headlights come on. Would have though it would have put side lights on only during the day[/quote]

i've read somewhere that lights also get switched on when wipers get switched on, not sure though.

btw, no concept of switching side lights. if its dark its the headlights that come on. so either head lights or no lights. no side lights.

no concept of switching on side lights as per the law either.

Certainly on my old E53 once the auto wiper 'wipe rate' hit a certain cycle speed then the headlights came on too. Front sidelights never come on with the auto lights. One thing that used to puzzle me though was why the auto lights always came on whenever the sky was a clear cloudless blue in the middle of the day, even when the sensitivity setting was lowered by the dealer.