Re: Need your help! Brake lights not working.
Originally Posted by
ImportLabSRT
Like said above....you can try swapping relays. If the lights still do not work, my money is on the BOO switch. I worked at Mercedes for 4 years and replaced dozens of them on other chassis with the same part number switch.
In a perfect world, you would have a multimeter or at least a test light and I could walk you through a few steps to diag. Main thing is to see if you have voltage coming into the BOO switch and voltage out when the plunger is depressed. If you have voltage out, then next would be to check the relay.
The OP says the relay clicks when the pedal is depressed so I would imagine the brake switch is working. That's what I see from the circuit layout. If power is coming out of the relay to the light switch is a different matter.
If the plug is pulled from the back of the light switch then power should be evident at pins 2, 6,5 and seven when the pedal is pushed. If power is found only at pin 2 then the light switch is faulty.
That's my guess anyway.
Last edited by onehundred80; 03-14-2014 at 10:05 AM.
Reason: Circuit added