Im having a nightmare with my 53 plate e60. I think I have an odd electrical issue as if I leave the battery disconnected over night, in the morning, the car will either start and idle fine or start then die. If it starts, it either dies shortly after driving off or after it has warmed up.

Before it dies, the interior light comes on dimly and then it just dies, this could be after driving fine for a little while. More often than not, the car wont restart.

Ive noticed that my drivers side rear light cluster has failed. Not one bulb is working, even though they all look fine.

Pressing the brake pedal sometimes turns the interior light on.

I disconnected the light cluster in question, but the car still wont start.

When it did this previously, I disconnected the battery and left it 5 minutes, then reconnected the battery and tried to start it. As soon as I got to position 2, there would be a loud thump from the rear like somebody kicked the bumper.

I took the car to an indy and they were baffled as it started and ran fine for 20 minutes. I have tried several different batteries including a 1350cca monster.

The other day, it had been sat for a few days and I went to start it and it fired up, I drove down the motorway for a few miles and the steering angle sensor warning came up and the indicators didn't automatically cancel. It then told me the boot was open and the car gradually lost power, eventually stalling.

I have disconnected the ibs, but this hasn't stopped the gremlin.

Does anyone have any ideas to try?

 

Was the alternator checked ?

 

sounds like a bad ground or short somewhere. but where do you start?? maybe the brake pedal circuit...

 

I'd get the error codes read

 

He said he did check it because I thought it might be that.

Ive cleaned up the ground point and tightened it down properly. What module is responsible for the lights and where is it?

There are none

 

not the battery ground, but where anything electrical in the car ties to ground. i'm not sure where all the grounding points are though.

 

check for water ingress on electronics modules? It seems odd to me it would be shutting down after already running. Must really be dropping serious voltage if so.... I have some electrical schematics for e60s but I am not sure if it is going to be much help since there are SO many.

 

Take a voltmeter and check the voltage at the positive terminal under the hood. Take the voltage reading while the engine is off. Then start the car and take another reading while the engine is running. Can you tell us those numbers?