FWIW, per the W124 Service CD-ROM, the W124 with the factory alarm should not draw more than 80-ma when ARMED, 60-ma when UN-ARMED.
After eliminating all FUSED sources, the MB Factory Alarm (un-fused) was found to draw an extra 90-ma when ARMED. While no specification is listed, I am assuming this is too high.
The other 20ma was found to be a combination of my integrated hands-free cell-phone kit, and an aftermarket one-touch window module.
I would suggest that whenever adding new electronics, one should document the new current draw (off, idle, in-use) at the fuse-box for later troubleshooting.
1988 360TE AMG