What does the BASESP dash light mean on a Mercedes ML320?
It means it has an error, it can be several things. Hopefully it
is just a sensor error which is cheap to fix vs a new computer
system which can run $2k plus. Best bet is to replace the brake
position sensor first and if that does not fix the problem then you
have to go to the dealer and have them diagnose the car for you,
most dealers will do that for free and if it seems like an easy
problem that you can fix just buy the parts and make it an
afternoon DIY.
After replacing the break switch if problem continues to exist
then replace the relay that can be found under the hood inside the
fuse box. look for (esp/bas or I guess #38).