Cheers Davey

I have just bought an E320 which had no power to courtesy lights, mirror, sunroof or wiper sensor. I used your video to take the dome down to get the part number and found someone had pulled out the power supply plug. Plugged it back in and everything works.

Thanks :-)

 

Nice, but what was the problem Again?
1mm partial section of a via missing??
what is a via?
Mine also stopped working and I know this is after fiddeling with the Overhead OCP I think is called, broke the rain sensor wire, bought new one installed but Command always stay in nightmode display (Set to auto)
AutoWiper runs every 5 sec
Guess need fix some issue in the OCP and then get a Star reset and re-learn the rain sensor..


What is that Little sensor in the Rear Mirror on the front site looking like a microphone??

 

FYI
Deleted

 

Better late than never.

I have since sold my beloved E320 CDI.

A via is a part of a pc board that is used to pass a signal through all layers. They are round, and I have an arrow pointing to the failure on the via. Before trying to track down a unit with the same numbers to replace it, I'd recommend to check for water damage and possible short and a missing section on traces in your unit. I probably have higher than average soldering skills, so if you don't feel confident repairing traces (if you locate a bad section) take it to someone that is. I had always kept everything working perfectly on the E320 cdi but it was sometimes pretty challenging.

 

Greetings friends. I have a 2005 E320 CDI, and I too am facing issues with the rain/light sensor being inoperable.

Last month I was away for an extended period of time while my beloved car was parked outside and exposed to the elements -- including some substantial rain.

When I returned from my trip, I realized:

• none of the OCP functions were functional,
• the rain/light sensor was not working, and
• the interior lighting was not working either.

(Note: All of these functions worked perfectly before I left).

Following recommendations @Mad Davey outlined in this thread, I initially charged the main battery and then replaced fuse #9, both to no avail.

I then replaced the OCP with a used unit sourced on eBay and upon doing so most functionality was restored including: interior lighting, rearview mirror functions (HomeLink, map lights), sunroof switch.

Unfortunately, the rain/light sensor is still inoperable.
The headlights are set to "Auto" and come on even when it is daylight, and the COMMAND unit stays in night (dark) mode.
(Note: If I pull fuse #9 to stop power going to the OCP, the COMMAND unit goes to day (light) mode, and there is no change with the headlights).
I replaced the rain/light sensor wiring cable ("harness") with a new cable and there was no change to functionality.
I also cleaned the windshield around the lens (where I saw no issues), and try the various "reset" procedures, also to no avail.

If I have the rain/ight sensor disconnected, I do not receive any warning messages -- which leads me to believe the OCP doesn't "see" the module.
(Note - I did not receive any messages when the OCP was not functional either though)

I am now contemplating next steps as I continue working this towards resolution, and wanted to get feedback from you all.This car is my daily driver, which I love dearly, and having these features are much appreciated.

Thanks for taking the time to read my post and provide any much needed guidance!

Please let me know if you have any follow-up questions that I can answer to help provide guidance.

I will keep this thread updated with any/all findings and ultimately resolution (once we get there). ​​​​​​​

David

 

Hey David, that's a pretty hood account of your troubleshooting steps

Take a closer look at the Rain sensor internals... it may feature an unsoldered connector. If so simply resolder 4 junctions then done!

The other thing is you really need a scanner to read what the modules firmware is up to. It's not just a bunch of hardware, it also thinks and communicate through many CAN modules and gateways... so problems often have different fixes.

Given so many details, it takes a fair mind to pin a single cause.
🤞

 

Hey @CaliBenzDriver .

Thank you for the quick reply. I pulled down the rain / light sensor module earlier to get a look at it and note the part number, but I have not opened it up to look at the internals yet. Thanks for the suggestion.

Do you have any recommendations for a scanner? I spent some time this past weekend searching online for a scanner that would be best and possibly include the ability to "code" modules but didn't have any success identifying one that might be best.

Thanks again,
David

 

the most popular scanner is the icarsoft, I use Autel and some people use factory Xentry.


connector pins...
We can't see if the pins are properly soldered or simply pressed in...

 

Have an electronics tech take a close look at your original OCP if you still have it, it seems likely water may have caused some damage to some traces, maybe you'll get lucky and have it be reparable like mine ultimately ended up being. My final fix was simply to repair the original OCP, this avoided having to figure out if the new OCP needed to be recoded in the car, or even if it could be. This was a very frustrating issue.

 

Hi ​​​​@Mad Davey ! Thank you for chiming in, and for documenting your journey online in this thread. It has been very helpful!

I do still have the original OCP. I can take some pictures of the board and post them here. Any specific parts I should be sure to include?

Since everything connected to the replacement OCP is functional except for the rain/light sensor, I have ordered a used rain/light sensor (MB P/N: A2118206026) and am hopeful it will be what is needed to fix the automatic wipers/headlights.
If that doesn't do it, I will likely breakdown and take the care to a trusted local independent MB repair shop to let them run diagnostics perform any recoding should it be needed.

It is very frustrating indeed. I couldn't agree more with you about having a love/hate relationship with this car!

Thanks,
David

 

Take a close look at my post #24. That is the internals of the OCP and the arrow points to where it collected water, then mineral deposits shorted the trace, I cleaned it off and repaired it. To clarify, the water shorted it, part of the trace blew like a fuse so the metal was missing off the board. I replaced the missing section with solder and fine wire. I have experience with such repairs.

 

Got it. I will review the black cover of the OCP to expose the internals and take a look. I am almost positive my OCP failed due to water/mineral deposits having collected. Once I get it opened up, I will locate that section and take and share some pictures. I have some soldering skills and can certainly take a stab at the repair if that is what is needed.

To confirm, did your OCP lose all functionality like mine did, or was it just the rain/light sensor? I'm wondering if the one trace being shorted (if determined to be the case) would cause all the functions to stop working, or possibly if there are other traces that have also shorted. Guess we will hopefully know more once I get it open! Again, I will share some pics once I get a chance to get into it.

Thanks @Mad Davey !

David

 

Oops.

 

David, see post # 1 for my initial post where I describe the symptoms. I simply do not remember the fine details at this point. I remember the final solution was to solder a trace within the OCP next to a light bulb as you can see in post # 24. Doing this would have substituted all other troubleshooting such as changing the OCP and rain sensor. I did not fully realize you passed over my solution, as it may have saved you some trouble at this point.

I started this thread 8 years ago and no longer have the car. All I buy is Lexus now because I got tired of chasing two problems at once at any given time, and having nightmares about breaking the transmission or something else. If I had my own large shop complete with lift I may have kept it. The 2005 E320 CDI Engine and transmission may have been the most reliable, powerful and efficient transmission and engine I've ever owned. The 722.6 5 speed and cast iron diesel were both the last of their kind. It really was the rest of the car that required so much that got me to give up. The car was 100% dialed in, in perfect working and serviced order when I sold it at close to 100k, with added bluetooth, new flex disk, new suspension ball joints and arms all around, new shocks, new rear sub frame bolts, new motor mounts, repaired the navigation twice, repaired OCP and more when I sold it. I believe the gentleman that purchased it got an amazing value since most people don't let something like this go easily. I do miss the car but I'm also happy it's gone. Little defects drive me nuts and I will keep chasing them. I only owned the car for about 40k and never have I had to put so much into such a nice running car to keep it perfectly operating for so short of a time.

 

Hey ​​​​@Mad Davey . Looking back at post #1, it looks like the rain/ight sensor was your only issue with your original OCP.
My situation is different as my original OCP lost all functionality, and after replacing my original OCP with a used one, only the rain/light sensor isn't working. All of the other functions are working properly now.

I took the black cover of my original OCP's PCB and took some pictures. It looks like it may be too far gone, as I see several areas that appear to be damaged.
I am not sure if attempting to clean the PCB and resolder trace is those areas is an option, but would love to hear your opinion.

I couldn't agree more with you about the amazingness and longevity of the 2005 E320 CDI powertrain.
I am the third owner of my car, and it now has 402,500 miles (yes, miles).
The first two owners (who are brothers) were meticulous and I am the same way.
I promised the prior owner I would keep it on the road and in tip-top shape to best of my ability, so I am going to make good on my promise the best I can.

I appreciate you responding to this thread even after having moved on to another car/brand.
I too left little defects drive me crazy. I guess you could say I am now "OCP OCD" and will be until I get this resolved.

Thanks again for the correspondence and your guidance.

David

 

@Mad Davey I was able to remove most all of the mineral deposits with some alcohol prep pads. Here are pictures of the PCB after wiping it down.

 

I would take out both light bulbs and clean everything more thoroughly. I still see the hardened mineral deposits that may be causing your issue. The white stuff around the bulbs, especially the left one. I see a via that may have some damage possibly with a pin (not sure), but I'd have to take a close look. It's above the left bulb in your photo. Possibly one below as well. I'd really have to look close myself with a light. If you have a light with a magnifier it could help you here.

 

Still needs work..

 

Thanks @Mad Davey . I will do some additional cleaning and re-examine the state of the board under magnification.

 

In your photo, I see one Via that is certainly fried out completely, another I labeled possibly damaged looks like it may be lifting and it may have disconnected. Vias are a pathway for power or any electrical signal to get through the board, for our purposes here, it's usually as simple as from one side to the other. More complex boards can have layers and it would be difficult to fix, but I suspect these are simple two layer just top and bottom. They are the round things. If one was totally fried out you could simply run a small wire around the board to and from a solderable area of the same connection (making sure it doesn't get pinched). These are intricate connections, it would be easy to do further damage without the proper equipment and experience.

 

Also FYI, I believe the large black round thingy is a light bulb you can twist and remove in case that was not obvious. IMO it looks probably fixable. Understanding the via, and what it does, and some higher than normal soldering skills are probably the key to this repair. Among other things, I used to solder 200+ pin memory chips for various hacks, no easy task.

 

Yes sir, it is indeed a removable light bulb.

Based on your examination, I think I will abandon attempting to repair this PCB (from my original OCP), keep the replacement OCP installed, and keep my fingers crossed that the replacement rain/light sensor I've ordered will do the trick. If it doesn't I will likely bite the bullet and take the car I to the shop to get it diagnosed.

Thanks again for your time, @Mad Davey !

 

I wouldn't call that clean just yet:


oxides bridges galore 😳

The target is 100% clean, no less. All oxides gone, all tiny coper traces repaired then coated/isolated.

Evaluate if that's do-able before spending 3 hours to get to 90% but unable to reach 100%.

Asses if any spots are wasted, start with these though areas.

From there decide to quit or continue ...

 

The electrical current caused the minerals in the water to solidify, and along with the water cause shorts on the board, in this case it shorted so bad it damaged parts of the traces including where they pass from top to bottom. You need to restore the original pathway for the signals. The most challenging one I labeled damaged Via, you might even fit a kynar wire or some copper strands through the old via and solder from one pad of the parallel connection to another determined by looking at the traces and possibly using a continuity meter. Cheers, if it works you owe me a beer.

 

oh man, I would totally fix it... ugh. CaliBenzDriver indeed many more electrically hardened mineral deposits he should remove. Still good to clean but sometimes these things stop shorting after being dried out completely, but the largest ailment is the obviously burned out via, and I'd check that other one that looks like it might be lifting with a continuity meter from an adjacent pad on one side of the board to another.