The brake light switch failed on my 2000 ML320 on a trip this past spring. Stepping on the brake pedal would not disengage cruise control either. That switch must control a lot of things. I thought that it was pretty serious that it would not cancel the cruise control when a truck pulled into my lane!

george d

So recently my wife tells me that she's been driving around with a pen in the transmission shifter because the shift-lock stopped working again. Now, here's the weird part - when it's warm outside it seems to work just fine, it's just in the cold weather that it doesn't work.

So - today the car is at the dealer getting the catalytic converter replace from the recall. The dealer refuses to look at the problem without charging a diagnosis fee, which sucks. My thought is if they have the car there anyway, and are replacing a major part, at least they could do will be to plug in the computer (which I assume they'd have to do anyway after replacing the converter) and check for fault-codes with my transmission.

FYI - The brake lights do work, and so does the cruise... why would temperature come into play?

Rob

any updates on this ? the ml55 is doing the exact same thing but i would like to make sure that the brake switch is the culprit.
thnx.

__________________
Whether you think you can or cannot, Either way you're right!. by Henry Ford.

I was on an online chat w/Pat Goss (Motorweek) and his comment was "Check the lock solenoid (brake shifter interlock), solenoid adjustment, and brake switch."

To all you experts out there...would one of these make more sense if the problem only happened when it's cold out?

I have accomplished one thing though - while driving I knocked the pen (which we use to disengage shift lock) hard enough to break off the spring loaded tab, and get it jammed in the hole. Luckily I was able to get it out, now there's just a hole...

..sigh...