i'm having a hatchback water leak issue with my 2003 R53 & water is getting in the kar accumulating in the battery box
does anybody have any suggestions as to where it's coming from?
maybe from a bad gasket for the third brake light up top?
....before i attempt to remove the third brake light up top, i was wondering if anyone else has had this hatchback water leak issue & what they did to correct the problem
thanks in advance for any help or insight on this issue

 

I had a minor leak once through the wiper motor shaft hole.
Also, the tail lights and exterior grab handle on the hatch are culprits as well.
If you start removing the interior panels you're likely to see evidence of where it's coming in.

 

test it with a water hose. start at the bottom and work your way up. so

tail lights, handle, bottom of window, window washer, third brake light, top of hatch, antenna on roof

 

I'll put my money on the lower window trim. I've had 4 Mini and each of them leaked at that point. The rubber gets hard and water goes down into the trim clip holes. To test this, remove the tailgate cover (inside the car), close it and spray water onto the trim. Do it a few times because it needs some time to find its path. Then go into the car, lay flat and look up into the tailgate, past the wiper motor. You should see two of those white trim clips accumulating water drops.

 

Mine leaked from the failed gasket of the boot handle/license plate lights assembly. I removed the inside trim on the boot and had my daughter spray the hatch until I saw where the water was entering.

I replaced the gasket but we do not get enough rain in my area to know for sure that it is fixed or was the only leak.