I resoldered the idle control board on a '81 380 SL per these
instructions and it worked fine. Also, there is a reference to a
rebuilder of Mercedes analog control boards which are a real problem in
older MBs. These include cruise control, idle control. and climate
The idle control is up above the passenger's left foot, above some
cardboard. Bit of a bear to get to, but not as bad as some other
things. Its an aluminum rectangular can, IFRC held by one 10 mm nut.
The long term solution is to buy a Toyota, but you probably already