BMW Rain Sensor Problem
 

I really like my auto wiper system, much more than I thought I would, and would hate to lose it.

This has to be asked: did you activate it properly? I'm sure you did, just asking.

I don't buy the bubble thing. I have looked through thousands of windshields and I have never seen fields of bubbles. And it is hard to believe they would appear just in that small sensor area.

Also, the system requires a fair amount of mist and rain drops to turn on. This would be equivalent to a huge number of really nasty defects in the glass. And if there were a field of bubbles, the wipers would be on all the time, thinking it was raining.

I think it is either activation problems or a defective sensor. Or maybe whatever module controls all this. I am sure there is a fairly simple electronic test to find out what the problem is.

Lastly, on many vehicles with sensors or other fancy options, OEM glass is used for replacements. Sometimes owners are adamant about getting that little BMW etching back. So, that insignia is not proof that the WS has not been replaced.

Glass shops, especially the insurance-friendly cheapo ones, are notorious for breaking wires, using the incorrect adhesives and all that.

So, back to the testing idea. At least you would know what the problem is.

If windshield is not OEM sensor is fail or sometime , like it was in my situation , did not work at all. After installation of original BMW glass rain sensor workin just fine till present time ( about 2 years since ).
Now if your winshield is original , first try to take ( borrow from other guy ,who has the same model x5) a new sensor ( 200 usd usually) replacement is fearly easy and you can do it yourself. Be caryfull with plastick hooks on windshield ,when reattach sensor itself, by not braking them .
If that does not help ,-you need to replace a stearing wheel column regulator. Step by step. Good Luck
please revieu when you'll finish succesfully

After several years, the moisture will cause gap between the windshield and the IR receptor and the field of bubbles will become bigger and bigger until the sensor malfunction. I try to post a picture here to show you how the sensor works. In fact, the rain drop on the sensor area causes refraction that diverts all the IR away. The bubble in this area block the refraction and therefore the receptor always receive signal (IR) and assumes no rain at all. The reason why I do not want to change the windshield because it may damage my car (have you ever seen how the technician replaces a windshield - it is so appalling!). Unless there is a crack on my windshield.

http://img249.imageshack.us/img249/6...itworksrg3.jpg

I had this problem before, it was definitly the air bubble. I went to a local automible glass shop in Hong Kong and replaced it with OEM windshield, it then works fine till now. The rain sensor had no problem at all. Don't worry about the cost for windshield replacement. If your insurance is comprehensive insurance, then you can raise your claim for accident damage of windshield. Otherwise, it is just HK$4500 (around US$550). If you want more infomation, email me at [email protected].

Hi Roger, thanks for your advise. I am comprehensively insured so I will give it a try later.

Hi bbbngai

Thank you for your post. Same problem in HK since 2006. I have an interest for your point 2, pleae let me know details and where can I found the materials gels?


Hi Roger

On the insurance issue, I understand we can claim the whole OEM windshield, but we only can claim when the windshield really damage and need to report to police, it is right? In my insurance policy, insurance company only allow us to replace the windshield on their nominated company and they charge around 6.8K. Any comment???

Yes, you are correct. The insurance company only replaces your windshield for accidental damage. However, you can just break the windshield by yourself and report to your insurance company that the windshield is broken by a small stone when you are driving on somewhere like Eastern Corridor of HK Island. You do not need to report to police, just report to your insurance company. Actually the repair company will teach you how to raise the claim to your insurance company. Generally, the insurance covers HK$8,000 for replacing the windshield per year, so 6.8K is no problem.

DIY replace successful
 

:DSo happy.

I fixed the rain sensor now.:thumbup:

Did you use Permatex to re-attach the rain sensor?

why did not you write what you did.....after all.........can you give us a breaffffffffffffff?!
frriendly

By the way, the rain sensor RLS module does have an adaptive memory to compensate for a dirts or chipped up windshield, and that adaptation can be reset.

Yes, I use the Permatex 66BR but my friend said other silicon have same function.

Before I decide to do the DIY, my rain sensor has mal-function for a long time and I only have auto headlight functionally. So I think if I screw up the sensor system, I only loss my auto-light and it is not a big deal. If you same as me, try to start the work.

1. Take out the cover of the rain sensor (RS) behind the mirror. Unplug the cable of the sensor module. Push down two hooks on the both side of RS and take out the RS module. DON’T touch any inside surface of the RS. (This is the easier step.)

2. Now you can see a plastic bracket with some sensor eyes attached onto the windshield. Use a marker or tape or any method to mark the position of the bracket (I forgot to do this and then I can’t re-install the cover of the sensor)

3. Use a thin & sharp knife or cutter to cut the existing silicon in between the bracket and the windshield. Try to cut in surrounding method until you can twist the bracket with a little space. Then CUT & then TWIST…… If you can turn around the bracket, you become successful to move out the bracket. This is the most difficult and danger step, be patience and be careful. DON’T damage the surface of the bracket and windshield especially the coating onto the windshield. DON’T use the front sharp point to cut the silicon, use the knife body to slide into the gap between bracket and windshield. BE CAREFUL your finger and hand when you use the knife or cutter. Carry on turn around the bracket until it can move out.

4. After move out the bracket, use your finger to push out all the old silicon on the bracket and windshield. DON’T use any tools because it can damage the surfaces. You can use the industrial alcohol (85%) to clean up all the remaining silicon. DON’T clean up the marker on step 2.

5. Read the instruction of the 66BR firstly. Apply one or two horizontal rows 66BR on the middle of the bracket and don’t apply too much to the both ends. Use a flat plastic sheet (I use a cake sheet) to make the 66BR smooth and even and flat for cover the sensor eyes locations. To stick the bracket to the windshield onto the original position and apply a little pressure to let the bracket evenly. Let other person to observe the sticking condition outside the windshield to avoid the air bubble. Add more pressure to release the air bubble. Then DON’T MOVE and DON’T SLIDE for few seconds (maybe 10 or 15 sec.). Leave the bracket and re-confirm the right position. (This step is the most critical.)

6. Open the roof and front door to let the good ventilation for an hour. After that, you can use your car but don’t touch the bracket within two days.

7. Two days later, see the result of the bracket attached outside the windshield. If there have no air bubble and the silicon look even, you can re-install back the RS and cable. Otherwise re-do again and apply more 66BR. Test all function of the rain sensor and auto-light.

P.S. Un-plug and plug the cable, don’t insert the key.

After all function tested, I put my car outside under sunshine for 12 hours to test the 66BR. That's no problem.

Finally, my results are:
A: Cannot put back the cover onto the right and fit position because I forgot to mark down the original position of the sensor, then I need to use a tape to fix.
B: Auto light function have seen some delay btu still function, maybe I applied too much 66BR. Try to apply thinny.
C: Rain sensor is function but I need to activate once time on raining to start the function. Then it can stop when no rain and it can start when rain again. The intermediate step can function now, also it can stop when the car stop to move.

resurrecting an old thread. Same thing is happening to my x5 as well. My head lights will sometimes turn on in the dark when set to auto but sometimes they won't come on at all. My rain sensor wipers are not working at all so I'd assume this is the problem. I have 2 small bubbles when I look at the sensor from the outside.

Reading this thread, I would assume I don't need a new sensor module but just need to take out the IR receptor and re-apply it onto my windshield without any bubbles?

@weasel- How do I reset the adaptive memory? maybe I should give this a try first before trying to reposition my IR receptors onto my windshield.