6ml500

I'm brand new to this forum and this is my first post. Thank you in advance for any assistance. I have woken up to a dead battery over the past few days in my 2006 ML500. I took an amp draw after 20 minutes or so to let the modules go to sleep and the draw was 2.6 amps. On a side note the ESP light has been intermittantly on over the past few weeks. It comes on and stays on immediatly after starting the car. Not sure if this is related to the battery drain. I started pulling fuses and relays to narrow down the problem. There are a dozen or so fuses that are contributing to the power draw. Most notably the radio (1.1 amps) and the diagnostic outlet (0.43 amps). The seat modules are also drawing a bit of power. I took the navigation DVD out of the radio to see if the amp draw would change. It did by 0.18 amps, even after letting it sit for a while. I think that whatever module that puts the radio and Command system to sleep is not doing so. I also disconnected the main power cable to the alternator to rule out a diode draw.

I dont really want to take this to the dealer if I dont have to.

Any suggestions would be really appreciated.

Thanks

biker349

a lot of people have found that the power seat control switch can be faulty. try either disconnecting your power seat controls, or taking the fuse out that controls the power seats and see if that solves the problem.

6ml500

I disconnected both seat modules and only noticed a slight draw on each one. I think it was around 0.07 amps. It seems that most of the draw is related to the radio/Command system. With the key out of the ignition I can press the stereo power button and activate it. I dont know if this is normal, or a sign that this system is not being turned off properly. Is it possible that there is a short in the system that is causing the battery to drain as well as the ESP light to come on at start-up? If so, how could I test this?

6ml500

Last night I disconnected both seat modules to see if this would fix my battery draw. I woke up this morning and the car started perfectly. The ESP light was off too. I drove it on and off for the whole day and everything was aces. I am going to leave the modules disconnected and try again tomorrow morning. Is it possible that one of the seat modules is causing the Command/radio functions to not go to sleep?

My plan is to see what happens in the morning. If it starts ok and the ESP light remains off, then I will reconnect one of the seat modules and see what happens the next day. Then repeat for the other. Im hoping that this will narrow down which module is causing the issues.

I also need to put the nav DVD back in to see if this is a contributer to the problem, but will likely try this last.

biker349

it's probably the drivers side, or the side you use the most. good luck.

6ml500

I reconnected the drivers side seat module yesterday to narrow down the porblem. The car started right up this morning in -5C temp. This would lead me to believe that the passenger side module is the culprit. I am going to however run it like this for a couple of days before I reconnect the passenger seat module to see if it sustains a charge.

Dritschel

Have you resolved your issue? I have a 2005 ML500 and after 2 to 3 days, the battery is dead. I have a new Interstate battery, CCA 720, CA 900, RC 176. When I put a multimeter inline with the battery cables, I only see a draw of 0.29 amps. If I check the volts on the battery, every hour, seems to lose about 0.02 volts per hour.

Thanks