Help! Parasitic Drain
 

My wife's new-to-us 2000 C230K has a parasitic drain that has me stumped. After a dead battery, I checked for a drain (ammeter between neg post and frame) with a reading of .27A current. After a couple seconds it would drop to .04A, then .08A, then back to .27A. Pulling 7 different fuses would lower it to .24A, then the cycling again.

Question: What would cause it to cycle like that? (Fuse designations seems to point to the window or door modules)

TIA!!!!!

I dunno about Benzes, but GM uses window and seat motors with internal circuit breakers. If a switch stuck 'ON', the breaker would heat up, open, cool off, and close. The result is very much like you describe...a now-you-see-it, now-you-don't current draw.

Disconnect the battery and let everything cool off for half an hour or so. Then, when you reconnect, you might be able to hear where the problem is.

power drain
 

Try unplugging the seat computers. I worked on a C240 that had a bad passenger seat computer that would keep all the other control units "awake". If you have a bad control unit connected to the CAN it can keep all the others from going into the "sleep" mode and powering down.