E30 Zone

Brake light warning indicator comes on randomly even though brake lights are working fine('89 325sport).. Any ideas?

Brake light warning will always come on when the ign is switched on,then go out the first time the brake lights come on.

as above it comes on with ignition then goes off once the brakes are used (or the brake light is lit) but it uses a type of resistance bridge system to monitor if the bulbs are working., and once triggered the light stays on. in your case one of the bulb holders is likely worn causing the bulb to wiggle about in the holder, then at one point it wiggles seperate from the bubl holder, this fools the system into thinking it has an open circuit and turns on the light. you could try puiting some tape or papaer around the base of the bulb to jam them into the holder a bit tighter to see if that helps, if it does not then your wiring is proabaly at fault, most likely around the plug of the rear light cluster.

The most common cause of this problem on RH drive cars is that the brake pull rod, which links the pedal box to the bell crank behind the glovebox is badly overdue for adjustment.
Small amounts of wear in each part of the linkage add together to let the brake pedal drop far enough from its stop for the brake switch to be on the point of lighting up the brake lights. They flicker, and the high inrush currents fool the bulb sensor into thinking one has failed. If this is left too long, the brake light switch itself will fail as well.
The pull rod has a RH thread at one end, where it screws into its end, and a LH thread at the other, so loosening the lock nut and turning it changes its length. It should be adjusted so that the brake pedal is just short of its upper stop.

Ok, thanks.. I know about the test after ignition, this happens at random times when i press brake.. I know it does it when the brake lights are working because it's happened when i can see reflection in garage door etc when reversing.. cheers for the advice, I'll check those out at weekend.