Connect a test lamp between the positve battery cable and the post. If the lamp lights with everything off, leave it connected and pull fuses one at a time until the lamp goes out, current draw is on that circuit.

Naturally, it's likely that something unfused can do this too, but you will at least eliminate everything fused.

Once you know which fuse it's on, you will need a wiring diagram to determine the location of everything on that fuse, and test.

Possibilities are radio antenna motor staying on, relays stuck, trunk or glove box lamp on with trunk or glove box door closed, interior lights staying on and you don't notice, and so forth.

I'm tracking down exactly the same problem on my brother's SDL -- got a 0.75A current drain on fuse #15.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!