visit your local dealership

 

Blinking sounds like Pre-Safe got activated. Did this happen during normal driving? Have fault codes read with Star.

 

Started blinking and was parked in the driveway. Scaned with Star Diagnostics and got a code 9011 "The actual value 'Stop lamp switch circuit 54' input signal supplied by control module N93 (Central gateway control unit) over the CAN is implausible." I disconnected all wiring harnesses from the brake booster and the brake lights are still on !?!? They should be off. The '07 W221 does not have a brke light switch so thats not the problem. There are no warnings or codes on the dash.
I even went further and replaced the rear SAM hoping it was that, but nothing helped. Does anybody have any idea what it could be ?? I appreciate all the help.

 

Could it be a bad N93 module under the steering column making the lights turn on ? Does the N93 control brake lights among other things ?

 

Not sure what the problem could be but I believe the brake light switch function is moved to the boosters sender unit, but you said you tried that. Also you said you replaced the rear sam which I believe needs to be SCN coded to the vehicle and needs to be done at the dealer even if you have your own personal star. Did you have any issues with the new sam? I think with the money you are throwing at it replacing parts might outweighs the benefit of having it done at the dealer. Good luck!

 

As you have observed, this is a computerized car, brake lights are not only driven from a direct input from the (previously) "brake light switch" but brake lights are activated from other triggers too. In this case it sounds like a control unit (was it rear SAM?) did not get proper messages from the CGW and switched brake lights on "just in case". Better to have brake lights on even if not intended than the opposite.

Have you checked the CAN distributors and the connectors to the CGW (looks like you already did that at the rear SAM).

An interesting fault anyway.

 

A brake is a device which inhibits motion. Its opposite component is a clutch. The rest of this article is dedicated to various types of vehicular brakes.
Most commonly brakes use friction to convert kinetic energy into heat, though other methods of energy conversion may be employed. For example regenerative braking converts much of the energy to electrical energy, which may be stored for later use.

 

We are responding to this old thread in hopes the information will help those who may be searching for a solution.

We see this all the time on W215/W220 models - Brake lamps are on anytime the key is in position '2' - In STAR/Xentry, it's easy to check the operational status of the brake lamp switch. It is also easy to check the signal status of the Rear SAM. In almost every case, we replace the ESP/PML/BAS control unit and the problem is solved. Leave the key on for 15 minutes. The ESP/PML/BAs control unit will be hot to the touch with this type of failure...