Since purchasing my 2006 ML350 about a year ago, I've been having some peculiar issues with the electrical system. I'd love to say that Iknew exactly where they were coming from, but to be honest, they almost seem to be "ghostlike" and mysterious in their causes.. However, one commonality that they all share is that they occur almost exactly when traversing high altitudes or in mountainous environments. Here's the details:

On April 24, 2009, as I was making my way up the mountains east of San Diego, CA (Imperial County) at about 4,500 feet when my dashboard indicator popped up with a "Check Engine Oil" warning." As I had just had the oil changed and refilled at the MB dealer only weeks earlier, I shrugged it off. I eventually checked the oil level once we stopped about a half hour later, and it turned out to be okay. I never gave it a second thought, because about a week later, the warning went away.

On September 3, 2009, as I was traversing the Blue Ridge Mountains of West Virginia / Virginia at about 3,500 feet when my dashboard indicator signaled three messages: "Brake Lamp, Right Substitute Lamp; Brake Lamp, Left Substitute Lamp; Brake Lamp Left, Substitute Lamp." I was immediately bothered by this series of messages so I stopped at the next exit to get some new bulbs. I replaced the two bulbs which were referenced, the Left & Right Brake Lamps, with exact replacements, the Sylvania 7506 (although I got the Long Life version, 7506LL). I tested them, and they still did not work. I assumed it was a fuse or relay that was blown. I checked to make sure that I still had brake lights, which I did (the combination "Tail Lamps" and the "High Mount Stop Light"), and continued on my way. The indicator warning message continues to come on every time I start the vehicle, and the only way to "clear" it is to acknowledge it with the steering wheel buttons.

On September 8, 2009, as I was crossing back from West Virginia / Virginia to head home (at about 2,500 - 3,500 feet), I had yet another electrical issue - the electronic climate control in the front center console area "stuck" at a constant temperature and fan speed (the coldest albeit). Even more, the lights and program control panel associated with the console were maximized at "Max Cool" with all bars illuminated, and the driver's side controls (Windshield, Center/Torso, or Feet directons) were unable to be changed or not illuminated. The passenger side front controls were able to be changed to different temperatures and directions. This problem continues to occur, along with the above issue with the brake lamps.

Does anyone have any ideas as to why this is happening? Is there some sort of gyro or altimeter that is being "tripped" when I go to higher elevations? I live at sea level along the coast (formerly West Coast, now East Coast), so altitude is not normally an issue for this vehicle. Is there some sort of reset or button/programming combination that can be done to circumvent this problem or eliminate it now? I am now outside of my original warranty (40,000 miles) by a few hundred miles, so taking it to the MB dealer is no longer an option unless I want to pay some serious $$$ for diagnosis. Any help is greatly appreciated!! If necessary, I can take some photos and post them to assist..

 

it sound like you have 3 seperate problems. the brake lights have a updated socket because the contacts on the original ones get burnt and dont make contact. there is a software update for the ac control mod that sould fix the ac problem. not sure what the oil light could be. hope this helps