My 2008 550i with the N62/TU engine & automatic transmission, with 185k miles seems bricked! I absent-mindedly did not pull any codes before it completely lost all electrical functions.

Here is the rundown:

A few weeks ago (on my beloved 2008 E60 550i), I noticed the tail lights staying on after turning car off. After locking the car, the tail lights stayed on and then the 3rd Break Light came on and stayed on. All lights would turn off after restarting or just pushing the start button without foot on brake pedal. This happened every time I drove the car. I tried all headlight settings with the same results.

About the same time, I starting hearing a buzzing sound coming from fuse panel above battery in trunk.

A few days later, at night when I turned car off, headlights stayed on and went off and on many times like they had a short.

A few days ago, I could not get the lights to turn off, no matter how many times I restarted the car or just pushed the start button. I pulled the two 40 amp light fuses in the glove box fuse panel. The lights went off but the battery was drained overnight.

Yesterday, I pulled the spare tire out and found that there was a little water in the tray that the modules are in and a little water under the tray in the bottom of the trunk. I found that a seal at the bottom of the rear glass had dry rotted and was evidently leaking.

I pulled all of the modules and examined them. After opening the RDC module I discovered that water had been in the module and caused quite a bit of corrosion. (pics attached). I tried unplugging the RDC module and removing the 7.7 amp TPMS fuse.





When ignition turned on, there was still the buzzing sound behind the fuse panel above the battery for 5+ seconds (video attached). I then disconnected all of the modules in the same area as the RDC module that could have water damage. There was still the buzzing sound behind the fuse panel above the battery for 5+ seconds.


Today, I attempted to start the car to get codes from my Carly for BMW app but it would not start and then would not even release the fob from the ignition, no lights on dash..... nothing. Seems to be a complete electrical system failure.

I have searched the internet & YouTube with very little help.

Any help anyone here could provide would be GREATLY Appreciated!

Cheers!

 

I don't see what the question is. It looks like you've known what the issue is. Take the fuse box out and find the part, wire or whatever it is causing the short. Replace the bad modules and you should be good to go. Am I missing something.

 

Try some jump leads on it, this may help to get it started and allow you to get some codes from it, you’ve already found at least one water damaged module that needs replacing.

 

Pull the fuse bracket out and locate where that buzzing sounds is originating from. Might be a wonky relay.

Water may have leaked around down in that area as well.

One time I found several inches of water surrounding my battery.

 

Personally, I would not put any power to the car. It may cause more damage to other modules that are not bad.

 

Thanks for the reply. Apologies for not being more clear about my questions. I would just love to know if anyone has had a similar experience and knew what I should try next. I was not sure if I needed to pull the fuse box and physically look for something in particular. I had been applying power via a halo bolt from the engine compartment contacts. This may have caused further issues. I will reconnect all modules except the fried RDC module then go and pull the fuse box (no water detected in this area) and see what it looks like on the back side.

Thanks again for taking the time to reply!

 

My concern would be knowing if it is a relay if you do not see any physical evidence of damage. The time to find the buzz was when it had power. Usually that sound comes from a relay but I dont see any on the panel unless that is one in the bottom left corner. Make sure you look good for and damage (dried water or burns). In the mean time you should be looking for a replacement RDC module. They are fairly cheap on ebay for a second hand. Ensure you match the numbers when buying. Once you get the replacement you should relocate it so it does not happen again. I am surprised it even happened because there was a recall on modules in the spare area for the dealer to have them relocate it to prevent that very issue.

 

Thanks so much seanjordan20! I'm looking for a video on how to remove the fuse panel, hopefully without causing any additional issues. I'll give it a thorough inspection and take closeup pics.
I have gone thru the process of entering my VIN at BWM and a couple of other sites. It always comes back with 0 open recalls. The Catalano class action suit settlement covers: "Only cars less than 10 years old with fewer than 120,000 miles are eligible". Unfortunately, I don't think BMW will help any with this problem.

 

Fuse box diagram shows that the "Battery Current Saving Relay" is located in the middle far left in the V of the red positive cables. It has numbers written in white on it. I will pull it and attempt to test it.

 

If its not the relay, then check carefully for exposed wires. You can also unplug those connectors one at a time.