Originally Posted by chealse-tractor
Really appreciate the reply. You have confirmed what we though in that it was down to the wiring being oxidised/ damaged by the water getting in.
The Wire connects to the BAS unit or a black unit on the passenger side below the washer bottle this one end ends in a plug that connects to the unit Ithink it was a black plug in colour and the rest goes hangs down by about 6 inches then goes back up into the the enginee bay but where this goes we are unsure it is a thick mass of wires. The one that was chaffed was a thick brown wire about 3-6mm?? in diameter. From what we can remember off top our heads there are 2 brown and 2 red thick wires the rest are thin different coloured wires.
My partner is going to try and get back to MB again today and speak with the workshop manager and see if he can tell us how far that goes back and where too but if you have any clues they will be greatly received. Least we can rule out the Control box at £950 quid. The laugh is when they did the testing they said they checked the wiring but never said it was chaffed. so we know they never looked at it.
According to the wiring schematics there are two large Brown wires coming out of the ESP module and travel together to the left rear of the engine compartment somewhere near the master cylinder where they are spliced together. It then leaves that location in ONE single Brown wire where it travels to the left front of the truck where it is grounded behind the left front headlight.
The Hydraulic Unit under the washer bottle has ONE large Brown wire leaving it and heads directly to the same ground point, behind the left headlight... Hope this has helped.