posted on Jul, 17 2013 @ 09:29 PM
So as some of my fellow gearheads know, and have read, I recently acquired a BMW X5. The rain sensor quit the other day. The issue was a gel pack that
maintains optical clarity for the IR sensor that looks through the winshield to "see" the rain drops. The gel pack dried out, and got blurry. I
guess Bavaria doesn't see 105 F. that often as it does in Texas.
It was going to take FOREVER for the new gel pack to come in. Were it not under warranty the gel pack would have cost $212 plus labor. If the sensor
were damaged during replacement which is possible, but not likely, if the tech were even a little bit careful, a new sensor is $430.
I am an impatient critter so no way I was waiting weeks for this little gel pack to come from Liepzig, or Munich, or whatever. Plus the new pack
would be just as likely to dry out again. eventually the vehicle will no longer be under warranty, and it will be my tab to pick up.
So I found a great solution. A lot of other manufacturers use clear silicone to apply their IR rain sensors. Same operating principle, so in theory
it should work. I removed the sensor from behind the rearview mirror bezel. It was really easy. Chucked the defective gel pack. Cleaned the sensor
face, and windshield mounting area with a microfiber cloth, and squished a big glob of clear winshield sealant on it. OK... I did it carefully so as
not to get any air bubbles, or sealant on the headlight sensor also in the array housing. Then slowly smooshed it back on the windshield at a slight
angle so as not to trap air on application to the back of the windshield. Viola! perfectly clear, no air bubbles! But will it work? I grabbed a glass
of water, and started flinging droplets at the sensor... swish... swish... went the wipers YAY!!! It works perfectly, and the silicone will never dry
out, and stop working. The tube of silicone only cost about $6, and it took me about 20 minutes to do the job.
The dealership didn't mind either because now they don't have to fix it, and if I have an issue in the future they said they would play dumb.
I like to pass on little tid bits like this to all my wrenching buddies... so there ya go ATS grease monkeys.