Trying to sort out battery drain problem
 

The car is a 2003 S500. The ONLY symptom is the battery draining down overnight. With everything turned off, doors closed, the trunk open, the trunk latch mechanism manually closed and allowing enough time for everything to go to sleep, the amperage data are as follows: 0.4 amps for 4 minutes, 3.4 amps for about 30 seconds, 1.4 amps for about 1 minute. That cycle keeps repeating itself for as long as you monitor it. I used an icarsoft MBII to read out and reset all codes. The codes that repeatedly come back are show in the attached photos. The central gateway passes its DTC test. There are no SRS lights (or any other lights for that matter) and there are no symptoms associated with the transmission. Basically it is a normal car except for the battery drain and the codes shown. Actually, I do also get code B1341 "Fault in communication with component H3/1 (alarm signal siren with additional battery). I have ordered an alarm siren for that. Can anyone possibly shed any light on this?

It's the alarm siren box

they contain a lithium battery and they are all dying at this age . The battery is not replaceable the whole siren box needs to be replaced with a new part , don't get a used one as the batteries are just as old

Thanks, I ordered a new one earlier today since I know the siren isn't working and it could be the cause of the battery drain. Some say it can be the culprit, others say it can't. I'm still a bit confused by the codes in the pictures being repeatable yet don't seem to manifest themselves in any other way. I was hoping someone could explain the cyclical nature of the amperage data.

Just replaced he alarm siren. The alarm now works, but it did little or nothing for the battery dran issue. The amperage continues to cycle as described above except the 3.4 amp 30 second draw seems to have dropped to 2.7 amps. All else remains the same. Any ideas?

Time to pull fuses 1 by 1.

Might be a module in the doors/seats.

Also take out the navigation disc . Often times the radio is not fully shutting down

The good news is that pulling the F61 fuse (Voice Control System, Telephone System, and Emergency Call) brought the amperage draw down to a normal, constant 0.03 amps. The bad news is that the radio volume has been muted as a result of pulling that fuse. I assume this is related to the Emergency Call function of the Command System. I could care less about voice recognition, telephone or emergency call. Any suggestions as to how to either unmute the radio system or fix the underlying problem so that the radio will function normally?

Update.
Just discovered that I am getting an SRS light with fuse 61 pulled.

You can bypass the voice control module , Mercedes sells fiber optic bypass cables you'll need

my voice control module got water damaged so Mercedes dealer just bypassed it and the rest of the stereo works fine