ML350 battery drain puzzle
 

Have a 2004 ML350 with a battery drain issue I can't figure out.
Battery (1 year old) and alternator have been tested and are good. I had a current draw of 1 amp after being shut off for 30 minutes. I pulled all the fuses one by one and no change in current draw. I disconnected the seat modules and also no change in current. I disconnected the tele-aid box and the current draw goes from 1 amp to .46 and then to .03 amps within a 1 minute time frame. If I connect my ammeter probes again the current goes through the 1 amp to .03 amp cycle again. I have left the tele-aid box disconnected. Battery is still draining after 12 hours so that I can't start the car. As I understand it this model of ML350 does not have a SAM. I also checked the alternator to make sure there was no back flow of current due to a bad diode.
No lights are left on etc

Anybody have any ideas????

. The fuse for the radio needs pulling out ,just to see if its the radio .But dont do this if your radio is coded .And do you lock the car at night so it closes the computers down .You could take a fuse out every nigh to close items down , then it would show up eventualy the culprit .Lots of checks on youtube videos for voltage drain .

I come up with the same as you --no sam in 2004 ml350 2005 did have one in the rear ,. Go to youtube and put in the search box -- --- The Trainer #26 Using Volt Meter to find - Key off -Battery Drain .

I don't lock my car at night. I live in an area where I don't lock the cars and sometimes keep the keys in them. So the computers will stay in the awake mode if the car is not locked? Has aftermarket radio in it and I have pulled the fuse to it with no change. I had the battery tested at Advanced auto and they said it was good but needed a charge. I then had Walmart take the battery out and run a test and they said it was bad and would not hold a charge so I bought a new battery yesterday. Will know if that was the issue by tomorrow.

You will get a drain if its not locked. .The car needs sleep mode

No.............

Check in fuse box near rear lower part there is a small fan used by aam to cool the module box , I think its powered by aam and not a fuse , unplug it, usually radio is common culprit also

info
 

Please give us your explanation then, not just NO .

Could you clarify where the cooling fan is located? My fuse box is under the hood, drivers side and also one in the kick panel passenger side. Is the module box you are talking about by the fuse box?

No means "no". Leaving the car unlocked will NOT kill the battery. How about you give your source and prove him wrong? Most people leave their vehicles unlocked in the garage (and a lot of other people simply leave their vehicles unlocked!). Pretty sure we'd have heard about Mercedes issuing a recall by now for batteries being drained from doors unlocked... They'd certainly be the only manufacturer to have that problem.

^^^^
Thank you. Dis300

Turned out after a new battery the tele-aid module was the culprit. Pulling a steady 1 amp. Disconnected and the current draw is .03 amps. After disconnecting the module the SRS warning light is on now.

Curious if that means your SRS is now compromised or disabled somehow?

Same issue here - 2004 ML350 battery keeps draining
 

Have already had battery replaced twice - once by AAA guy when the car wouldn't start and the AAA guy came in and said it's dead and sold me a new battery. Two weeks later dead again. This time had it jumped and took it to a mechanic - he replaced the battery saying AAA is trash and put in an "interstate battery". Two weeks later same result. Now that it's cold in the mid-atlantic it is dying overnight every day - I jump it in the morning, drive it around a bit check the battery voltage when the engine is running and it was 14.4V, then about 12.6V when I shut off the engine. Next morning come out to start it and dead - Voltage is down to between 10.8 - 11.0V after just sitting overnight. There is something on this car that has gone bad and is pulling current. I am the original owner of this car (bought new from dealer in 2004) and this never used to happen but has now started happening since the last few months. I can do the DMM testing of the current draw by pulling fuses but wondering if there are known culprits I should check first - of course the teleaid is one I will definitely check but are there any other known culprit modules or circuits on this car that people have had experience with?