W210 Lamp failure indicator

[paulapps]

Brake pedal causes indication that can not be cancelled, all lamps ok. I changed pedal switch which fixed it last time. Front ns side lamp comes on with brake pedal what is it?? maybe clashing contact in rear lampholders are again the cause? I had the problem once before with the holders and the front ns side lamp coming on and bent them and fixed it. I was told rear lamp holders have been redesigned - have they?? My Austin seven had no lamp failure warning and never needed it is the most infurinating feature of this good car.

 

[Uncle Benz]

Seen this before. It is probably the bulb. One of the double filaments has broken and dropped across onto the other one. IE the brake light filament is now powering up the tail light filament. Have a close look at the bulbs and you should spot it.

 

[jberks]

I second that. I've even had a car that was powering the engine this way. Side lights on, brake on, switch off the engine and the engine carried on running! Foot off the brake and the engine stopped. Quite simple really but had me scratching my head for 5 mins before the eureka moment.

On a brake to sidelight short, the tail bulbs are strong contenders. Remove both and see if the fault goes away, the pop each back in turn.

I also had to 'maintain' the rear bulb holders on my 210 to stop the warning light coming on. The brake lights looked ok but after a few mins with a screwdriver and some wire wool, the difference in intensity of the light from the bulbs was staggering. It impressed me really as whilst the warning that a bulb had failed was incorrect, it was right in that they weren't anything like bright enough.
Could be worse, I had a Ford escort. The rear bulb holders in that were a nightmare!