Replace the fuse in the overvoltage relay. It is under the hood at the rear of the engine and has a red top on it. There is a 10a fuse in it that will blow if jumpstarted. If the fuse isn't bad, it may need the whole relay. We sell them in the partsshop.
1981 280GE SWB
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM