Hello everyone, I'm not incredibly savvy when it comes to car mechanics and tech so I'll try to be as descriptive as possible. Ive had this car for about 10 years and these problems started about 5 years ago. I can pinpoint it to an event but don't know if that is the true cause. I spend most of my time away from the car unfortunately so don't get to give it the love and care it needs but try my best. Im now trying to get it back in working order but honestly do no know which direction to go and steps to take.

5 years ago my wife decided to accidentally leave its trunk open while it heavily rained for a few hours. Once she realized this she closed it, and then when the rain stopped she opened it back up, threw in towels to the back and let it air dry for the next few hours. This appeared to have no real impact on anything from what it seemed at the time. Months late I believe the eco stop/start system wasn't working anymore and the rear side door ambient lighting would flicker, but the other accessory functions were not affected from what it looked like (such as the push to hold brake).

3 years ago after a cold start the car suddenly wouldn't use turn signals. No sound or lights for them. The rest all was function except just the turn signals. No hazards either. It was an isolated incidence and just blamed on how maybe some sensor was blocked or something (there was snow the day before).

2 years ago now one day an error came up saying Pre safe disabled, lane departure disabled, blind spot disabled. This wouldn't affect driving but those assists were in fact disabled. Sometimes they would just correct themselves mid drive, sometimes on the next starts, and other times not until weeks later. Hard to correlate but sometimes it seems after a heavy rainfall, but that might just be coincidental. Once it seemed going over a hard bump suddenly fixed them, but also could just be chance. This has been going on till date.

About a year ago, all of that, and traction control disabled would come up, and much like the others sometimes would fix itself.

Earlier this year about 4 months ago I replaced both batteries, as accessory battery replacement error came up. This actually fixed the eco start stop and brought the back (although to be fair the feature was never missed, now I have to turn it off intentionally)

Since the last 2 month, in addition to the pre safe, lane departure, blind spot, and traction, its showing errors of adaptive headlights, cruise control, ABS inoperative. Few days later when started it showed for the transmission, do not shift. It suddenly went away, but she didn't drive the car just parked asap.

Since then the car has been left off and and I started it yesterday. It struggled to turn on and eventually it did (I assume long time no use, but I think she had started it in between for the battery). It had all sorts of lights on and Brake light was on too. The steering wheel buttons seemed to not work, and even command took several tried to press something. Eventually it wouldn't even recognize that the key is not inside momentarily. Even turning it off became a hassle as it wouldn't register the push to start click, had to manual pull out button and use key to turn off.

I have not idea how to go about getting this back in working order or even diagnosing the problem. I wish I had been around to keep upkeep but the few visits it was taken in the problem couldn't be reproduced and their scanner were showing nothing then. Anyone know what's going on here. Can't imagine every system is failing. Wiring? Component? Relay?

Any and all information appreciated. Thank you.

 

Water got in trunk.

whatever electronics are in there are corroded.

research what and where and get cleaning.

 

The learning curve is sharp. It seems you're dealing with standard MB issues ganged up.

The first step is to ensure good voltage using good AGM batteries and a float-charger.

The second step is to scan the chassis to get a comprehensive pdf report with a $130 LAUNCH scanner.

The third step is to involve a MB specialist for regular maintenance to help prevent expensive failures.

The fourth step is to focus on one item at the time to get results with simplicity.

 

I agree with others. First make sure both of your batteries are still good. After 10 years, they probably both need to be replaced.

Then do a scan with the launch creador and report what issues are still showing up. Note which codes are active and which are stored.

Then we can help you create a plan of attack...

 

Thanks for replying, the batteries were both replaced 6 months ago, parts were from MB dealership.

I'll look into the scanning and report back soon. Will wiring issues show up on that? and if so will they differentiate intrinsic fault for each system vs extrinsic causes like replays and wiring?

thanks again

 

The car has over 50 modules that all talk over various communication buses using the wiring. This is a blessing and a curse.

The blessing part of it is that the car can be pretty specific about what components it can and can't talk to which will give you a pretty good idea of where wiring issues are happening.

 

Sorry to hear of your troubles. Extensive to say the least. It seems obvious water intrusion is the name of this game, but of course conclusions can't be jumped to without some investigation.

Many modules live in the trunk. The 1st thing I'd be doing is disconnecting the main battery, removing all trunk panels/trim & visually inspecting the electrical connectors as well as looking for any obvious signs of where water could've been (staining, etc.) It can take years for water intrusion to show up in electrical faults (as in your case & many flood damaged cars). Hopefully you just have a module or two full of corrosion. Remember, your rear SAM (Signal Acquisition Module "fuse box") lives back there. This is one of the major electrical components of the car. If CAN communication can't make it in/out of there, the car will be very unhappy.

If/when evidence of water intrusion is found, you can use the part numbers on the modules themselves to look up what they actually control. This in itself doesn't necessarily tell the entire story, but is a good starting point & crucial info to have moving forward.

 

this thread continues... there