V8Connoisseur

Hello all,

I've been reading on here quite a bit lately trying to find a solution to my recently purchased ML with 123k I got Saturday. I've been trying to piece all the electrical information I've learned in the past few days together. I got the car with for an insane deal and being a Mercedes guy, could not turn it down. The previous owner did disclose to me some rather serious issues and I figured out a few minor ones on my own.

My main 2 symptoms which I'm almost positive are linked together are: the car won't shift out of park unless the car is warmed up for about an hour. I did just replace the auxiliary battery and the previous owner replaced the primary battery in December at the dealer. This did not fix the problem as I hoped. Voltage readings seem normal 12+ volts when off, 13.5-14 when alternator is running if I remember right. I know this is related to the red "Visit Workshop without shifting gears" since engaging the electronic shift lever will make it next to impossible to get it out of gear (luckily I know the trick for the time being) once parked. He did also state that on warmer days the car will take less time to "warm up" into the ready position. I have yet to see this as the weather has been pretty cool. I am almost certain this is not transmission related because when the car runs the 7Gtronic shifts excellent. It also was serviced at 40K by the dealer years ago. It does make a click (almost a calm clunk) when changing between P,R,N, or D. My C63 speed shift transmission never made that sound but it does sound like a 4WD pickup engaging its transfer case so maybe this is normal on a 4matic?

The other issue in relation to the shiftier issue is the dashboard does not light up properly and it seems to glitch on and off resetting itself, getting better as the car gets warmer as well. It throws a code that isn't too common (U0155 Lost Communication with Instrument Cluster). When the dash flashes and glitches the headlights and tail lights if in the off or Auto position flash off momentarily and the back on. I am aware of a sensor connected from the tail lights to the transmission as well that won't allow the car to shift too. Maybe that is it but I doubt it since they still flash in drive? I feel it is some sort of module that controls the dash and shift lever area though and electronics in that area. Maybe the SAM but I don't know, I don't even know what that is, just stumbled on it in a reading. There is an internal code too for cruise control malfunctioning and secondary til light bulbs are on. If you could share what that module is that would be helpful. the ECU and TCU are fine though. All other electronics function great. ABS, TCS, COMAND.

There are no blown fuses in the battery area, under the hood by the cabin filter, in the trunk area to the right, or in the area next to the primary passenger airbag. The previous owner AS WELL as his kids made a true mess of the interior too. There appears to be no drink spillage near the battery, but the back seats have stains underneath them when you lift them up with the strap as if a larger drink was spilled. I haven't looked much under there other than some quick vacuuming. There was a burned goldfish and a hotwheels car in the battery area. The car also is equipped with H&K sound, no navigation, and no air struts if that is helpful?

I am pretty good mechanically, but I have never had an electrical issue with a car so this is new ground (no pun intended) for me. Maybe it is not grounded correctly, though the ground points look ok and tight. Maybe I'm missing some hidden ones? Any help would be appreciated!

There also is a leak under the power steering pump where I added some fluid hoping that would get rid of the awful noise. It did fix the noise, but leaked right back out the next morning when it was freezing. I haven't looked at that much as its not a concern to me but if you know whether its a gasket or needs a new pump that would be helpful.

Lastly the owner had a brake job preformed at a euro auto shop but the steering still shakes rapid under intermediate braking. No warping, plenty of pad, and smooth rotors, but advice there would also be appreciated. Perhaps bushings or control arms?

Anyways, thanks for the help or at least getting through this as it feels like a lot. If a video helps, I can take one as well and it would be pretty short.

V8Connoisseur

Bump, anyone have electrical advise?

Maj. Dundee

I do not believe that it is an electrical problem per se but a transmission problem. You have no alternative but let M/B do the repair.

https://mbworld.org/forums/s-class-w...ing-gears.html

https://www.google.com/search?source....0.tBKXSGOEaKs

V8Connoisseur

If anyone comes across this thread looking for a solution, I replaced the gauge cluster and it fixed the problem.

hendy.yurinata

Hi there
Did you fix the transmission problem as well by replacing the cluster?