Question of wired sensor on top of 525I dashboard

[stevetag]

I just purchased a 2003 BMW 525I and in the middle of one of the defroster ducts, on top of the dashboard, there is a black sensor of some sort wired into the dash but, the sensor itself is loose and can be moved about 3 inches to either side.

Does anyone know what this is? I can't find a reference in the manual or online.

Thank you.

[brettski]

Welcome to the Werkz.

Does it look like this?
RealOEM.com BMW E39 525i Solar sensor

[stevetag]

Yes, that is it and, it isnt attached to any part of the dash and just floats around on top of the defroster vent. What does it do and, is it supposed to be attached somewhere?

Thanks so much for naming it for me!

[brettski]

I am not sure how it works on the BMW system, but the unit that was on my GMH Berlina detected bright sunlight and automatically bumped the climate controllled fan speed up one setting, and dropped it back in lower light levels. I expect that BMW are doing some thing similar, although I would have thought that it would be retained somehow.

[stevetag]

Thank you, that makes sense and yes, I can't believe it's not secured to something either.

Steve