Passenger door courtesy lamp
My wife's 1999 300M has a courtesy lamp malfunction on the front (passenger} door that only effects that door. The switch is O.K. because when the door is opened, all the other lights on the other doors come on. I replaced the lamp, but that did not solve the problem. Voltmeter showed the circuit through the lamp to be good, with 12 volts getting to pink wire but nothing (ground) on the yellow wire. I can find no diagrams fro this circuit. Can someone direct me to a solution to this problem?