According to wiring diagram, fuse 7 feeds the pushbutton unit at pin 12 (on the 12 pin connector on passenger side of pushbutton control). When any button except off and EC is pressed, 12v is fed from pin 6 via bk/rd wire to evaporative temp sensor. If this is correct, I have two problems. #1 - I have 12v from fuse 7, but 0v at pin 12. #2 -When I do a resistance check on the pushbutton control, I would expect to get continuity between pin 12 and pin 6 when any button is pressed except off and EC. This is not happening. I have a 1988 560sl. Schematic is 1987. I read something about the later controls switching the ground, but cannot find another schematic. Do I have correct wiring diagram? Any guidance would be appreciated. Thanks in advance.