I have a 1999 E320 with about 90,000 mi. I went out one morning and could not unlock car w/ remote key. After opening car manually all systems were dead. Checked battery was at about 2 volts.

After charging battery, I put an ammeter in series with battery and measure ~4 amps load. This is after all doors have been closed for 30 seconds and all interior lights are off. (I can see the current drop about an amp when the interior lights go off)

Then I pulled each fuse individually checking the ammeter after each was removed and saw no change in current draw. I pulled fuses from the driver's side under-hood fuse box, the under-rear-seat fuse box, and driver's side near headlamp switch panel and there was no change is current draw - it remained steady at about 4 amps. I also disconnected the trunk-mounted CD changer.

Also pulled fuses in the "brain box" under hood near firewall on passenger side. It contains the electronic control modules and a few fuses. I also disconnected each control module and no change in 4-amp drain.

I did notice that the drain decreases to about 2 amps after the doors have been locked via the key remote.

Does anyone have any suggestions about what to do next?

Thanks

 

Charge the battery overnight with a charger and then put a load on it and check it.Or get out your hydrometer.
Sometimes the dome light can be a problem on the w210.Are you running any led replacement bulbs?
ohlord

 

I wouldn't think you should have that much of a load on a parked car. A freshly charged battery would handle that normally, but not if it was parked for some days. I would suspect some accessory thing is 'on' or you have a closed circuit short to ground. Unless you're lucky, it's gonna be 'hunt 'n peck'. Maybe someone here has had exactly the same problem and will share. Bad bulbs will occasionally short out and although they won't illuminate, they will draw current-start sorting out your bulbs and bulb sockets.

Kevin

 

I am having the same problem on my '94 E320 but I think I have figured it out.

My central locking system keeps running and won't turn off. I suspected a sluggish linkage in one of the doors and tried to lube it as best as I could from the outside a couple days ago. (I sprayed WD40 into any orifice I could find) It seemed fine until this morning but alas I have the same problem.

Any suggestions on getting a more effective lubrication to the inside linkages? If it is a bigger problem, can I just disable the whole system?

Thanks for helping this newbie out.

Joe