In my experience, and adding that of "the board," there are two significant contributors to 240 battery drain events. Far and away the most common is the central locking being activated by the rotten insulation on the key switch or lock knob switch. A distant second is a faulty courtesy lamp delay relay, if you discount more obvious problems like a stuck glove box, trunk, or hood light. Following that in likelihood are various aftermarket-caused problems like radio preset memory being miswired or faulty security systems.

100mA is close to one glove box lamp, or one relay coil, but in the case of the central locking, the drain usually kills the battery faster because the lock motors get engaged, and current is limited to a low value by their "polyfuse" protection discs.

Fuse 8 is a good place to start. Measure the drain there. Remove the green wires connected to the fuse load side one at a time to narrow it down. If not at fuse 8, check the others in similar fashion: 7, 9 and 10.
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Art Benstein near Baltimore

Without geometry, life is pointless.