Mad Davey

Hello,


I have a 2005 w211 e320 CDI

My car has recently had the rain and light sensor stop working.

The wipers on the first setting work like any other cars, like once every 5 seconds, and the automatic headlight setting (first position) simply is always on.

The command navigation is always in night mode even in bright daylight and direct sun.

The only thing I can think is that I disconnected the trunk battery a few weeks ago to try to reset a seat problem, but I'm fairly certain it all worked until recently. We have had lots of rain lately.

I have tried:

-Cleaning the windshield at the sensor.

-Checked all fuses in all three fuseboxes.

-Shining a flashlight at the sensor to try to induce lights off.

-Disconnecting the trunk battery for a minute and reconnecting.

-Taking the overhead module down and disconnected and reconnected all connectors inside, also the connector to the sensor I plugged and unplugged.


I inspected the sensor PC board up close as well as the windshield and plastic optical elements and it all appears to be in perfect shape, I seriously doubt it is the problem. I have ordered another sensor with the same part number and will try that, but I have a feeling the unit needs to be enabled in the SDS or something like that.


Any ideas?

Stuttgarten

Try this: while car is running, have someone spray water with hose on windshield or better if it's raining, then go ahead turn wiper arm from off position to 3rd (fastest) setting, then immediately return it to off position turning it off, that should reset that function.

Mad Davey

I'll try it, but it seems weird the light sensor has quit as well. It occurs to me, I think I have tried that during rain, but I'll confirm.

Mad Davey

It did not work.

konigstiger

"Last effort" before having someone pull codes with MB DAS for definitive answer, check condition/pull f9 (OCP) @ rear SAM for a while, reinsert.

Nanook

Sounds like wire connection to windsheild unconnected

Mad Davey

I agree about the seeming lack of connection. I took down the overhead console and disconnected looked at and reconnected ALL connectors.

I'll try pulling the F9 breaker for a while, thanks for the idea!

Thanks for the replies!

Mad Davey

Pulled the breaker labeled "F" did not see F9, left it out for about 3 minutes, put it back, started the car turned on wipers to high then off, then 1st setting. Still fails.

I have a used sensor on its way, hoping that will be it, it's a very cheap attempt at fixing it $36 on ebay.

After that

1. I buy a SDS C4 on ebay for $600 and a Dell 630 for $100 and get some time for my new hobby of tweaking on my E320. I feel it will likely tell me the sensor is not responding, so go to #3.

or

2. Pay a shop to find the problem and repair it, likely to make me want to sell the car due to small problems costing lots of money.

or

3. Find the wiring diagram for the sensor and trace to see if it's lost connection or shorted.

or

4. Forget about it and just use the car as is, I have this car specifically for these sort of features and I find this depressing.

konigstiger

As a matter of reference here is rear SAM fuse assignments showing f9 http://www.google.com/url?sa=t&rct=j...,d.cGU&cad=rja

Mad Davey

Thanks, threw me off with OCP. I was thinking OPP, and thought no I would never do that.


Over Current Protection, could be anything, fuse or breaker.


Today I saw the F9, in the daylight, I pulled it out for a while, and no help. Crossing my fingers the replacement sensor will fix it.


Thanks again for putting some brain cells into my problems....


Cheers and Happy Holidays!

Mad Davey

I got the used rain/daylight sensor and installed it, no change at all. Any other ideas, or must I drain the wallet?

Tricks06uk

I have just had a thought, and it might be the answer, what are your opinions all ??

I have the same problem going on as Mad Davey and I have done all what he has done, save for changing the actual sensor- the reason for this ???......

Well I may be wrong, but my car went wrong after a period of cold this winter when there was lots of condensation. I took down the Dome light the other day because the courtesy light on my side, well the bulb wasnt working, having swapped the carrier from my side and using the same bulb and putting it in the passenger side, I noticed it worked. At the same time I note that the Light/rain sensor ribbon connects in to the same side as the malfunctioning light. Is it there for possible (particuarly as I noticed some small water droplets on the dome light fitting (the side which fits up in to the roof) that condensation or moisture whether that be from rain or ice or as I say condensation itself has entered the boards in the actual dome light on that side and knackered the board for the light and the light/rain sensor ????

I dont know, I have not gone as far as looking to see if the light/rain sensor are on the same board as the courtesy light, i would imagine not, but its coincedental that both the light/rain sensor and the courtesy light are not working.

If that is the case, trust me to have one that is particularly difficult and expensive to replace (with sunroof switch) as I suspect I would need to change the entire dome light and if so, would I need to then have the board for the light/rain sensor re-programmed to allow for the windscreen tint variant.

I suspect that it is likely that both mine and Mad Davey's problem lies witht hat OCP (the Dome light)

Feedback from anyone that works for Merc or knows more would be appreciated for my sanity !

Mad Davey

Good point, water may have somehow entered one of the modules in the OCP. I replaced my rain/light sensor with no change. I will put back my original and chase OCP problems. I have a rain/light sensor that clips in easily I'll sell you cheap!

Tricks06uk

Lol,

Thats really kind of you, but I think my problem also lies with the OCP

That said there are many variants of OCP out there and I found starparts to be quite expensive, but i did find this little site here - http://www.mercedes-parts-direct.com/. I went to star parts to get a quote and they want £225 plus £9 delivery, but for the same part the above site has the right one (same part number for my car) at just £90, a massive difference so theres a top tip for you !

I will be buying a new one possibly in Feb, and will let you know if you havent done the same by then ! (I also have to replace either the shocks, top mounts or ball joint in Feb so depending on those I may be able to afford the OCP too !)

Mad Davey

I ordered a used OCP from a local wrecker for $65 usd from a 2005, I'll post my results once it arrives. Thanks for the idea! I hate when problems like this get the best of me! I did note that before it went bad we had a tremendous amount of rain.


Wettest rain concentration here in California that I remember. I do recall a couple drips that I thought were odd near the driver visor and wondered if my sunroof had leaked, I was parked on a downslope with the drivers side lower and figured it best not to waste too much time thinking about it due to the unusual angle I was parked and the density of the rain and to chase it if it happened more.

Tricks06uk

Well, sounds like i may well have been right as that is almost to much of a co-incidence for my liking, I would love to hear the results, though dont forget that you may need to have the thing re-programmed on star (SDS) as there are many different tints on the windscreen and the sensor might not work if the programming is in the board on the OCP (i dont know for sure it is) but if it is programmed to a dark tint and say yours has a mild green tint, it can throw the sensor out and will need resetting on SDS - let me know of the results m8 !

Cheers

Rich

Mad Davey

thanks for the new hope. Keeping my fingers crossed.

Mad Davey

It arrived just now, I installed it and eureka. Used OCP for $65 fixed it! Here's the video you need. Note, check metal clips are not bent and intact on the replacement OCP, I failed to do this and had to replace all 4 clips while holding it up. NOT RECCOMENDED. Do not break the ribbon cables. To reinstall the mirror, you need to use some large pliers or similar to push in the pin on the left, there is an automatic spring detent that positions the pin and releases at the right time, that makes it possible to reinstall it once you do this.


Hope it worked for you as well! Check ebay for the OCP. I made sure to get the same year but it might not matter. I searched ebay for w211 dome light, and avoided the rear ones. People that list it as a dome light are less likely to charge buku bucks.




Thanks for making me think harder about this and collectively curing it!!!

Mad Davey

TO SIMPLIFY MY OVERLY COMPLEX POSTS. IF ANYONE HAS THIER RAIN/LIGHT SENSOR IN A W211 SEEM TO BE STUCK IN NIGHT MODE. THE ELECTRONIC MODULE IN THE OCP OR THE ENTIRE OCP IS A LIKELY CANDIDATE FOR REPLACEMENT.

Tricks06uk

A good guess then, I am totally glad it worked for you ! I thought as much, so baring in mind its happened to yours in California and I suspect from my own advice, mine in the UK, would it be fair to state that there is possibly a design fault with this then ?

Still regardless, at least we got to the bottom of it !

Good News !

Mad Davey

The "design flaw" may simply lie with an older sunroof gasket, which may have let a dribble into the wrong spot. That's my best guess. If I replace another OCP or if I notice water in side again I will consider that....

Mad Davey

I was wondering, does anyone happen to know if the temp sensor for the climate control is in the OCP? If not where is it? My temp control has not worked accurately since I replaced the OCP.

Mad Davey

I just looked at my old OCP, I suspect the 1 inch screened hole with a fan behind it is the interior temp sensor. I blew it out with a computer duster can. I may have to go back in there and put my old temp sensor in the new (used) OCP. Anyone performing this repair be sure to swap your temp sensor ahead of time so you don't have to go back in there like I may have to!


Update, my sunroof switch also fails with the new OCP.

Mad Davey

OK,


Second OCP arrived, same problem, the sunroof switch again would not work. Due to differences of circuit board design I have concluded the part numbers need to match or maybe it needs to be star programmed to work.


I took an even closer look at my original circuit board, after cleaning some water stains and mineral deposits off with alcohol I noticed a tiny trace had been damaged at a via from the water and minerals shorting it. I took an exacto and carefully removed the coating from the trace and soldered a tiny wire to patch the disconnected area. (image attached)


I find the best way to repair traces is to get a wire with high strand count, separate a few strands, twist them together, while still attached to the wire hold in place then solder the repair area. After it's in place cut with an exacto or fine flush cutters leaving the repair on the board.

Mad Davey

FINALLY FIXED!


I should also mention the water intruded in the low spot where the light bulbs sit and enter from the top, there is a funnel shape. For prevention I put a ring of contact cement and clear flexible plastic on the plastic shell over both bulbs to avoid water intrusion in the future. I am aware water should not be getting in there but again it was a crazy storm and I was parked at a weird steep angle. I also cannot remember if the sunroof had been opened for a second or not.

A small about 1mm partial section of a via missing was the source of my daylight/rain sensor problems all along!


I also want to mention it helps tremendously to have a helper hold the OCP while you are plugging and unplugging the wires from it.

I hope this helps someone someday. I would have loved to find this post before all this trouble!

E320 CDI is a love hate relationship....