My wife's '91 300TE recently had a battery discharge problem. I got to the bottom of the problem and thought it might be of help to someone.

The symptoms, besides the dead battery were:

1) Constant 15A battery drain with the key off.

2) Removing fuse "C" decreased current draw to 1A.

3) Removing fuse 9 decreased current draw to 0A.

The problem was a short circuit in the tailgate lock actuator position switch. The short circuit burned the insulation on the Yellow/Blk signal wire, the Red/Blk signal wire and the Brown/Blk ground wire.

As a temporary repair, I disconnected the position switch and insulated the burned wires. Everything basically works in this condition, however, the tailgate lock will not activate the central locking system or the alarm system.