04 E55 AMG: weird lighting behavior

Wiring, DIY, lighting, etc.
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kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

04 E55 AMG: weird lighting behavior

Post by kevm14 »

I have been noticing this on and off mostly since I've owned it. And I believe it may be a moisture problem in the front left SAM (smart fuse/relay box).

It surfaced again after I washed it this weekend.

The symptom trend goes like this:
- Car gets wet. Headlights in auto. I had been messing with some other settings like "surround lighting" which turns on the fogs and parking lights when you open the door and it's dark. Kind of cool, a little like later model Fords except the fogs add a lot more light. I also turned on the headlight delay to 15s after ignition off as I prefer this setting on my auto headlight cars. But this is when I started noticing the issue. It started when I noticed my battery was nearly drained a while back. This must be what drained it. The little red light next to the P on the shifter stays on and it acts like the ignition is not fully off, so if the lights are in auto, the lights stay on. If I turn them off manually, it still doesn't shut everything down. Eventually I messed with more settings and that seemed to fix it. But this was temporary.

- This weekend when I washed it (pressure rinsed), some of the symptoms became....elevated. At one point, the little red light next to the P on the shifter was just going on and off. A bunch of different stuff was waking up and shutting down (like the steering column lock). Not too good.

I pulled two codes from the front SAM with my Mercedes scan tool.
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I also did some sleuthing in my FSM (which doesn't make this easy). Apparently if I had the factory STAR system it would make this process much easier because it would give me suggestions about the code (that's right, I can't find info on these codes in the WIS system), and also allow a pretty thorough functionality diagnosis of any offending module (including the SAM in question).

But it seems like the EIS module (ignition module) is either errantly sending power to the front SAM to wake up (as in key on), or the front SAM essentially made this up. I will say during the issue I scanned the EIS and it NEVER commanded power to circuit 15R. Yet when I scanned the SAM it showed power and then no power on 15R. So I would think the issue is there. No codes in the EIS either.

Of course, this circuit is also shared with the wiper motor. And that circuit had the shoddy scotch lock wire tap which I finally ripped out (after the issue subsided with the car in the garage). I don't THINK that was causing anything but who knows.

Did some research and water issues are....common. My cowl cover has a seal up against the windshield and it is partially dry rotting. Water could be dripping down behind that and onto....something. Wiper motor, maybe even into the front SAM even though it has a cover. Maybe the wiper motor is soaked and back-feeding current into the SAM but it's not clear if it's seeing 12V errantly, or an actual wrong CAN signal. I don't think the wiper motor has a module on it.

So I ordered a new cowl cover (again this is common).

But Mercedes makes lots of improvements to their cars over time. So 05s and 06s got some additional anti-water stuff. One is this cover that actually goes on top of the SAM cover adding further protection. Ordered a used one from eBay.
https://www.ebay.com/itm/333132035041

Got that tip from my thread here:
https://mbworld.org/forums/w211-amg/787 ... t-15r.html

I am hoping that this will cure my issue. Worst case I'll have to pull the SAM out and see if I can figure anything out.

When dry, everything works properly, including the aforementioned lighting settings. So I think if I can fix the water issue I'll be good. So that's two water leak issues so far. I guess that's the downside to this thing living in a garage for 6 years...if it was parked outside it would have been fixed by now.
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: 04 E55 AMG: weird lighting behavior

Post by kevm14 »

Got my cowl cover and 4 retainers. Benzparts.com is doing a good job so far.
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I will try to put this in ASAP. That pipe is actually a drain tube that runs to the passenger side fender. So fancy.

It's funny. I remember when I first looked at the car, I did notice the dry rot along the base of the windshield. I thought, yeah well, southern car, that's how it goes. Well turns out they all do this. Also leaks there can cause electrical issues...that part sucks.

It poured on my way into work today. I saw no issues at all. In fact I learned that the automatic wipers work really well!! You just set it on intermittent and it does the rest. It will go from no wiping at all to high speed and anywhere in between as needed. I think they are better calibrated than the ones in my STS. In fact I have to praise the Mercedes unistalk here. To perform the single wipe, you press in the end of the stalk until the first detent. To wash, press past that. Simple. Well even in auto, sometimes there is a light mist or drops on the windshield and you just want to wipe once to clear it. In this car you can leave it in auto and press the button to get a single wipe. In my STS, you can't do that without taking it out of intermittent.
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: 04 E55 AMG: weird lighting behavior

Post by kevm14 »

Got the SAM cover.
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kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: 04 E55 AMG: weird lighting behavior

Post by kevm14 »

You know what that white area might be? Sun fading through the hood louvers. Maybe that's also a source of water onto the SAM and stuff. I sure did aim the pressure washer in there because there was some residual wax (or buffing compound).
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: 04 E55 AMG: weird lighting behavior

Post by kevm14 »

Did this last night in the garage. It was more fiddly than it would be on a less fancy car but still quite straight forward. The piece is more complex and sort of a tighter fit. Plus some of the retainers really didn't want to let go and I broke a few. The new one came fully assembled and I did get 4 new retainers.

Removing the wipers was easy. There are 3 arms because the center wiper has dual arms with a linkage. But I just loosened the bolts and they didn't take much at all from my 2 jaw puller.

I was also struggling at the end because I forgot about the drain tube which routes under the main cabin air filter. Then it was just sort of pulling and tugging.

The base of the windshield had some excess sealant that I peeled off so the new cowl cover would fit flush. I also had to peel off the old foam which was on the new cover. I cleaned the surfaces as well. Did not really see anything amiss regarding a leak but not sure what I was looking for anyway.
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More struggling and pushing and bending stuff to get this in. It's a fairly tight fit and the drain tube is just another thing that you have to fiddle with. But I got it aligned and eventually snapped in. It has built in retainers that snap in and then 4 external ones that look like screws but they are just push rivets.
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Then I cleaned my SAM cover. That stuff was mostly grime. Some glass cleaner got rid of most of it. I don't have the retainer clips so I just sort of put it in place.
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We had a thunderstorm last night and the car was in the driveway so I'm going to inspect now I guess. I did set my lighting settings back to the ones that seemed to cause problems before. We'll see how it goes.
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: 04 E55 AMG: weird lighting behavior

Post by kevm14 »

I see no signs of odd electrical behavior. The light next to Park wasn't on. The jury is still out - there are a range of conditions yet that I need to test. Particularly, I think shutting the car off in the dark and having the lights run that cycle while "wet" will be a good test. But so far so good.
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: 04 E55 AMG: weird lighting behavior

Post by kevm14 »

It rained yesterday. Not hard but for a while. No issues all day. Went to pick up takeout last night. Got home and tried the use case that caused issues last time - lights in auto, headlight delay, surround lighting on. It all worked perfectly fine. The lights shut off, and everything was normal.

Did I really fix this?? Still think it is too early to celebrate but it's certainly looking good so far.
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: 04 E55 AMG: weird lighting behavior

Post by kevm14 »

Car was wet this morning. Still no issues.

I may cross my fingers and hand wash it with the pressure washer next time and really see what happens...
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: 04 E55 AMG: weird lighting behavior

Post by kevm14 »

kevm14 wrote: Wed Jul 08, 2020 7:06 am Car was wet this morning. Still no issues.

I may cross my fingers and hand wash it with the pressure washer next time and really see what happens...
Washed it with the pressure washer as promised. Let it sit a couple hours during dinner and went to go around the block after. It was dark enough for the auto headlights to come on so this would be a good test, with the delay/surround lighting and all that.

So? It's fine. No issues at all. Everything shut off after the delay and the car is dormant as it is supposed to be.

As with the TCC solenoid, I am pleasantly surprised. So far I am doing well at knocking down these issues. Satisfying.
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