190D Battery Drain Solved...
 

Finally got to chase the Battery Drain that has been plaguing me for the last couple years. 1987 190D 2.5 N/A... Started with the mA Drain Test...bad news 90-100 mA drain! Not terribly bad, but enough to kill my battery in a week or so of sitting. Pulled Fuses, Isolated to Fuse 12! Good! No Problem, right? A quick look at the ETM showed I had a long day ahead of me. Alarm System, Courtesy Lights, Power Seats, Central Locking System blah blah. Decided after 20 different things, and one of the last before giving up.... to check the Alarm...disconnected the 2 plugs... BINGO! Now down to 10mA! A good thing for sure! So a silly question...does disconnecting the Alarm Plugs disable or otherwise affect any other circuits or systems? Search and didn't fing anything conclusive! Thanks!

In other words nothing important;)

I don't know. My suggestion: Drive it. Bring a cell phone. You will find out.