Today I discovered some water in the footwell at the drivers side of my E60. I’m pretty sure that’s the membrane in the door that has come loose. Is there anyone who knows if there is some electronics components in the floor at the driver side that can be damaged by the water?

 

When this happened to me I pulled off the door card, disconnected all the door electronics and replaced all the butyl tape seal.

The problem is when you take the door apart you don't have visibility. I was trying to see if any electronics were corroded or damage, but you can't see anything.

I used a ton of butyl tape all around the styrofoam membrane and the water leak stopped.

 

Check the scuttle drains too, this is a common problem and a quick check can save modules from frying.