Goroundthebenz

I found the other threads on this subject incredibly educational, loads of info thanks.
So I acquired this car recently and have the BAS , ASR lights each time she's started.
So I start with the engine off, push the brake pedal fully down and then start her up (still holding brake pedal down) and no warning lights come on for over a minute. Upon releasing the pedal all the warnings light up instantly .
So this seems to confirm the brake lamp switch fault that appears to haunt these cars. Relatively cheap part, some on eBay for £12 but I've read that a genuine part is worth the extra.
I also read that some have actually repaired the original faulty one and refitted with success. I will try this (when it stops raining...) and post pics if possible of the process

Goroundthebenz

I also noticed that the brake lights fuse (15A blue one) blows regularly, I have tried not using parking brake (handbrake) and this seems to stop the fuse blowing.
I'm curious to see if this is related to the defective brake lamp switch. Will update after I repair or replace the aforementioned offending item

Goroundthebenz

So I removed the old brake lamp switch and opened it up see pics, I noticed 1 of tthe 2 contacts on the spring loaded plate appears damaged. The spring appears to be ok. I'm assuming some arcing may have occurred and is causing the problem. I'll have a go at fixing this and update with results

Goroundthebenz

More pics

Goroundthebenz

So replaced the switch with a new one and hey presto all lights gone and my controls work again..... 4 hours later the brake light fuse blows and the problem is back ... Replace fuse and it keeps blowing , took switch back out and put it back and now brake lights stay on ..... Oh dear . Next task, dig out my multimeter and start doing some resistance checks me thinks ...

Goroundthebenz

So after I changed my brake lamp switch all 3 brake lights stayed on but warning lights for BAS etc went away... I removed the switch and checked its resistance and found it to be operating correctly. So why were my stop lamps all lit up as soon as I turned the ignition on ?. So I measured the voltage across the larger of the switch connectors whilst ignition on and got minimal difference ..... So the in and out were both live ?? So they must be crossed !! Stripped the black fabric covering off the cables and started tracing them back and BINGO !! Wires were fused together , the black/purple wires had melted into each other.
So I split them apart and for a quick fix just insulated them with electrical tape until I get some new wire and shrink tube etc .
Reconnected the switch and pulled plunger fully out and fitted it back to pedal and all is working again .
Hope this helps someone else out .

Matt Cruz

Completely off topic but i have been searching for months now and apparently have different system in my car from the others i cant figure out how to change my radio correctly to
Aftermarket i bought a connector from best buy nut its not correctly wired i did get my radio to work but it was with a
Beeping sound that i have too shut my car off multiple times till the radio sounds music the car does have a mb amp in it as well as a 6 cd changer the other sites do not have my radio wiring

MJ50

moved to W210 forum...