My cousin called me last week to help with his wife’s 03? R53. The car had an inch of water through it. After drying it we found the front passenger sunroof drain hose wasn’t connected. After pulling the head liner and having it recovered and reassembled. Now electrical issues. Windows, locks do not work but the radio interior lights and sunroof does. Also the 3rd brake light is on all the time. Not sure where to start, the 3 top fuses for the windows and locks checked good.

 

Depending on which side(s) came loose, I would check the Body Control Module in the passenger side footwell and the fuse box on the drivers side. Both usually end up damaged when a drain tube comes loose, along with corroding wiring harness connectors and pins.

This is a common issue and hose clamps should be added to the drain tubes. If you didn’t already do it, it should be possible without dropping the entire headliner.

 

Possibly to do with the rf receiver? Is that not around the clock area as well on that age?

 

Looked over the module inside and out and no visible signs of corrosion. Any where to get a wiring diagram I’ll start testing wires to and from the components.

 

If you can get your hands on a little scanner for the OBD you might be able to track down some error codes that may point you in the right direction.
I use the Creator 310+ and it works pretty well.

 

I’ve got an older SnapOn unit I’ll see if I can try.