this is probably useless - but here you go
i had the rear, and sometimes front lights intermittantly flickering.
put up with it for a week until i had time to search.
turned out - after a long search - that the earth wire off the 'puddle' light in the door had come off - and somehow this had contacted with the door frame, causing the lights to come on and off.
C140 420 CL
W114 280CE pimpmobile
W114 250/8 Hillclimber with M110 and bike carbs - got any hot cams?