Rain sensor - present but is it working?

[benth]

My 1st mode is completed: replacing a standard rear view mirror with a photochrom mirror - all works great...

While doing this I noticed that I have the rain sensor connected and powered up, but my wiper knob does not have the 'AUTO' words nor a LED light that the rain sensor is available. I think the rain sensor was simply not bought by the 1st owner that's why I don't see this on the wiper knob.

Would it be possible that during the manufacturing process of the car they simply add the rain sensor to every car but its just disabled on purpose?

what I have looks like:
https://photos.app.goo.gl/6EDN5YWTjE7vb7Ro9

while the 'rain sensor enabled' knob should look like:
https://www.weatherfordbmw.com/inventoryphotos/7614/wby1z8c30hv894772/ip/34.jpg?height=400

I did not try if the rain sensor actually works as there was not enough rain to try, but I think since I don't have the 'AUTO' words its not active...
would anyone know if I can make the rain sensor active since its already in my car?

 

[jadnashuanh]

I think first, you'd have to replace the switch so it had the auto button on it. THen, it MIGHT require a coding change to inform the vehicle to look for that signal. On some things, that information is present, but since there's no switch to initiate the message, all you need is the switch. Most things in BMWs are controlled by the computer and it gets its requests via a serial data bus (CANBUS) from a small module in the switch assembly. No message, no action. Message, but no programming to interpret it, no action.