pull the fuses one by one until the drain goes away. One you have isolated the circuit then start looking at all possible consumers on that circuit. do the ampdraw test all doors closed, key out and must be done in series.

__________________
1986 300SDL, 211K,Dealership serviced its whole life
1991 190E 2.6(120k)
1983 300D(300k)
1977 300D(211k)