imstock

So I have the famous, drive to workshop without changing gears, message in red. Vehicle is a 2007 R320

After looking it up I figured it would be the Intelligent Servo Module. Only thing is, I noticed I keep blowing fuse f111, which is the ISM for Direct Select (A80) fuse.

I unplugged the ISM and assumed that I would then be able to reinstall the fuse, but even with the ISM unplugged I still blew the 30amp fuse. Does this make sense? Could I still blow the ISM fuse even with the ISM unplugged, if its an ISM issue? Or is there something else wrong?

Anyone have any ideas? Id rather not replace the ISM if that isnt the issue.

Thanks!

imstock

Some things to add..

Ive pulled every fuse out of every fuse panel in the car, regular, maxi and even relays. Then plugged the ISM fuse back in and it still blows instantly.

Ive also noticed the only time this happens, is when it has rained and the car stays wet.

Also multiple things show up on the dash along with SRS, airmatic etc etc. Only when this has occured.

ItalianJoe1

Gotta find where the water is getting into the harness. There's a connector getting wet and shorting out blowing the fuse. I'm not familiar with the R class as we see very few now at the dealer, but i'm sure they have leak issues like every other Benz. Any wet carpeting in the van?

imstock

I did notice today that there was some water in spare tire compartment. I dont have the spare tire there anymore as I have been looking at the fuses etc. The water is by the passenger side near the fuse panel there. I unscrewed that panel to dismount it from the frame and look underneath to see if any wires were wet or had signs of having been wet. Nothing I can see, but I will still be trying to figure out where its coming from and see if there are any wires or connectors where it may be coming from.

Side note, I have only had the car for a week, just bought it used. (now i know why they sold it...and why there were so many burnt 30A fuses in the glove box) and I just found something else unusual. The yellow wire from the drivers side rear tail light harness is stripped and there was a long wire spliced into it and it was all the way by the passenger side tail light, but it wasnt connected to anything. It may have come off wherever it was going to...? Also the passenger side tail light harness has two yellow/black wires, both of them have a stripped spot but nothing going to them, not sure what it was all about. I did unplug those harness' in an attempt to see if that would help, but appears to be unrelated.

ItalianJoe1

Probably had some sort of aftermarket trailer wiring tied into the brake lights.

DO NOT let things get wet, find the water leak and fix it immediately. That kills these vehicles. Remove whatever you have to remove to ensure all the harnesses, fuse boxes, control modules, etc are dry and have never been wet, if there's corrosion on the connectors/pins you will have to clean/replace.

imstock

Also I am not sure what this hole is in the bumper, it appears to be factory, but is missing

open hole on bumper

JonMac

That hole is for a bolt to be threaded to when vehicle has to be pulled/towed from behind (rare~) .. the fact that it's missing usually indicates that it was towed at some point. There's one (larger) cover up the front in the bumper also

imstock

So fixed the problem. There was a wiring harness touching the CV shaft that had been rubbed through the loom, and guess which wire was rubbed through the insulation and was touching the CV shaft, the brown ISM harness wire.

I cut and spliced the wire back together and covered it with shrink tube, then zip tied it up away from the CV shaft. Problem solved!

imstock

Turns out I only have one reverse light working, When the wire from the driver side is jumped to the passenger side, I have reverse lights again, and the backup camera functions!

Im not sure what the issue could be there...cause if jumped from one light to the other makes it work, than the bulbs are fine.

Anyone have any ideas?

kjemad

my GL320 is doing the exact same thing. where was it rubbing?