high level brake light failed

Hi all,
had a look around but couldnt find anything on this. My high level brake light has stopped working. It isnt the bulb so I removed the lining from the rear door & the wiring seems ok in there. So is the high level light simply connected to the others somewhere? Is there a common cause of this problem?
All advice welcome.
cheers, Martin.

The wiring diagrams simply show it connected in parallel with the left brakelight.

I wouldn't worry, as it isn't tested at the MOT, and it only irritates the driver behind in a traffic queue

Have you checked for corrosion in the socket?

I re-read the original post, and if the wire breaks, it will be where it flexes on entering the door, not in the middle of the panel. Sometimes just the copper core breaks, and the plastic looks ok.

thanks all. If it spurs off the N/S brake light it shouldn't be too hard to find the fault...
Have to wait for some daylight first!

Hi, finally bothered to find/fix this problem so I thought I should close this out.
There was a broken ground wire (the brake light has its own) in the flexible section between the door & the car - as suggested above. Simply soldered it together & protected with heatshrink. The cables feel a bit hard so may be an age thing..