Steve360

I picked an '01 S55 recently and I'm having trouble with the brake lights staying on. I've had the brake switch go bad on my other Merc so I picked up a new one. This provided no change. I swapped in a known working switch with no change.
If I start the car without my foot on the brake, everything is fine. No malfunctions and the brake lights are off. The moment the brake switch is touched the brake lights come on and stay on until I shut off and restart. After the brake switch is activated I recieve ABS, BAS, ESP and ABC malfunctions. I pulled the stop lamp fuse(f16) and hit the brakes, brake lights still come on. It seems that without the fuse installed I should not receive power to the bulbs. This car has a brand new battery and bulbs as well. I'm kind of stumped. SAM modules show no sign of corrosion or having been wet.
Any insight is greatly appreciated.

Steve360

I thought I should to what I have done to try to fix this issue.
New brake switch
New rear SAM
New bulbs
New relays
Checked all wires and connections
One thing I noticed yesterday is that if only light press the brake down everything is just fine. When I press the brake past about 50% of its total throw the brake lights then stick on and I receive the ABS, BAS, ESP and ABC malfunctions. What confuses me the most the brake lights sticking on when this happens.

Steve360

I started checking fuses today. Found a 15amp with a terminal bent backwards. Noticing a few empty fuse holders I pulled the diagram out of the trunk to check it out. I have only gotten to the front left box at this but according to the chart there are multiple incorrect amperage fuses and empty spots where there should be fuses. Here is where it gets even more strange. Fuse F13 is empty which is listed for use in many different systems. Entrance lights, mirror indicators, power windows, interior mirror adjuster, locking system. These systems work but almost of them list an additional fuse used aside from F13. I guess my next step is to match the fuse box to the chart and see what happens.

Steve360

I was able to resolve this issue so I figured I should share with the group. I picked a carsoft scanner and was receiving a stop lamp switch error in the ESP module. I eliminated this part and wiring as the cause by swapping in a known good switch and tracing all wires. The other error I found was in the transmission module showing a faulty stop lamp signal coming from the traction module. I took a chance and ordered a used ESP module with the exact part#. $79 and 5 minutes later, I am error free and fully functional.