battery drain, command module, seat control modules and OCP s430 w220 2000

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dgc3

New Member
Joined
Feb 1, 2018
Messages
1
Location
Washington DC
Car
s430 w220 2000
have been searching for a 1.07A battery drain for over a month. have read most of the posts for the us mb sites and have not yet solved the problem. serial current drain finds 80mA for each door control module and 50mA for the instrument cluster (command module has been disconnected as well as seat control connectors under both from seats), leaving a 0.7A unaccounted current drain. the 80mA drains appear ONLY when the neg terminal is disconnected (since i am using the serial ampere measurement). reconnecting neg cable finds NO current drain at the 4 fuses powering door control modules. this would indicate that breaking the circuit resets 'something'. while reconnecting resets 'something' in a different way. please note that when battery is connected, car electronics are completely functional. everything works, and the car is driven daily (my 1.25A battery tender overnight keeps the charge full @12.9V). car running battery measures 14.3 V, so the alternator appears to be fine.

curiously with the negative battery terminal, command module and seat modules disconnected the overhead courtesy lights (in the OCP) will illuminate. one blog 4 years ago at this site ([SOLVED] - battery drain playing games :wallbash:) found an apparent link between OCP, command and seat control modules. since the OCP communicates with the rear SAM, i must consider that the current from the positive feed into the rear SAM can (somehow) turns on the dome lights, even though the battery is disconnected.

if anyone can confirm this possibility, or has other suggestions, i am most interested.

sincerely,
dgc3
 

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