I have already talked about this in a few posts before, so I won't go too in depth as I really don't know much about the issue.

My car ('11 CLS550) has an issue with water intrusion, possibly in multiple areas. It's been an issue since I bought the car over 7 months ago, but it only pops up when I go to an automated car wash, I suspect this is because of the amount of water, mixed with the high pressure dryers pushing water into areas it would otherwise not reach. It seems to me that water is getting into multiple computers, or the wiring between them. I have issues with door locks, interior buttons (mainly for the headrest dropping, and rear privacy screen) all of the exterior lighting, windows, etc. If i park it and leave things to dry out for a few hours, everything is fine again, I do usually disconnect the battery just to avoid any draw it might cause (that will come up later). The few things that are never affected are the engine, transmission, and airmatic. I assumed that it was caused by the Body Control Module, but from what I could find, these cars don't have just one BCM, they have multiple small computers for every individual system. That is what seems weird to me, because so many things go wrong all at once. I've avoided this by just handwashing the car, it never has any issues with that or even very heavy rain.

I recently went to the carwash, it was just a habit, it slipped my mind... of course, it triggered everything all over again, but it wasn't too big of a deal, I was on my lunch break so I had time to disconnect my battery and let it sit in the parking lot to dry whatever out. I went to close my trunk manually, and it refused to latch ( a new issue that has popped up ever since we had a big ice storm here in Tx). Of course I couldn't electronically close it, so my one option was to just leave the trunk open a few inches all day. Eventually everything dried out and I could close the trunk electronically with no issues, and drive home normally. I have no clue why it won't close manually, i've tried making sure the latch is fully open and not sticking, but for whatever reason it just won't close unless I use the button in the drivers' door. It's not a huge issue, but it certainly is annoying, and it sparked me to finally post about it and see if anyone else has a similar water issue, or any insight into what it could be. I know that the ECU's can have water issues, but it seems like it is everything BUT that. I do have major water intrusion into the trunk lid itself, but that never finds it's way into the trunk compartment, it just somehow fills the trunk lid with water, and the next time that I open it, it dumps it all out from the latch and the trunk light next to it. The only other spot in the entire car that I know can get wet, is on the left side of the trunk, right by the fuse/relay block, i have seen a few drops of water. I assume there could be a bad seal somewhere but I can't see anything.

I could take it to get everything diagnosed, but I would really rather pinpoint it down so that I don't have to pay for 50 hours of diag, or better yet, find the issue and fix it myself.

Thanks!

 

To start make sure water collector drains (under windshield) are clear if fine, check both front (engine compartment) & rear (trunk) SAM.