Brake Sw. and Stop Sw. are the same S9/1 Switch.

On ASR chassis , the switch is a double circuit switch , one for brake lamps and one for ASR...however, the ASR is a Normal ON sw and the Brake is a Normal OFF, So , b/c you get an ASR code without pressing the brake means nothing. You could have a bad contact in S9/1- ASR section and that is why you can get a S9/1 code regardless of brake application.. There are two likely possibles ..one is the new sw you got was not from Benz..this is a common problem with after-market ASR switches. The second possible is b/c of the fact that the ASR is ON when pedal is UP, you have to make sure the sw adjustment is correct or the sw can be open due to improper adjustment.

__________________
A Dalton