help third brake light not working changed bulbs but no change any ideas cheers andy

try removing the third brake light and check that the cables are still connected, they may have shaken loose and just need to be plugged in again, whilst the light is out, check for any damage to the wiring,

The wiring insulation in the rubber conduit between the hatch and roof tends to get brittle over time and after repeated opening/closing snaps the copper core.

Any breaks in the wiring should be pretty obvious, cut back to clean wire and crimp or solder in a new length of wire.

My old MK1 Focus ended up with damaged wires to the brake light, wiper, boot release and demister. The resulting short circuit meant a new wiper motor and boot lock module.