Check for water in the spare wheel compartment in the boot
I had to change my tailgate rubber seal and that sorted the problem
Was leaking like a sieve
Just sit in the car and get someone to spray a hose all over the back tailgate and side windows
Then check for water drips lol
Nice
You could always get the chain replaced to the newer type now incase
There's a lot more that goes wrong on the L322 compared to a 3 series
But if well maintained, they are fine
By the way, the link you posted doesn't seem to work ...
Bypassing it ?
Well you still need an amp for the Stereo to work
Short of fitting all aftermarket equipment a replacement or repair would probably be cheaper