Crazy trailer hitch wire problem
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Joined: Sep 2006
Posts: 156
Likes: 10
Crazy trailer hitch wire problem
I have an 08 ML 350 with factory trailer hitch, factory wired. my brother also has an 08 ML 350 with the factory trailer hitch and factory wiring. He has a small boat trailer that when pluged into his ML works perfectly, when I hook up the trailer to my ML and plug it in none of the lights work correctly, they all work but in the wrong locations on the trailer, pressing the brake pedal lights the running lights on the trailer, the turn signal lights the incorrect signal on the trailer etc. It seems as if the factory harness on my car has been wired wrong, My brother also has a pick up truck that when is hooked up to the trailer works fine, and someone else just towed the trailer with their Dodge truck last week and it also worked fine. I know this sounds crazy and impossible, but any other vehicle when hooked up to the trailer works fine. I wonder if there is a way for the dealer to change which pins on the 7 pin harness via the computer in the ML? I cannot belive that M.B. did not wire the harness correctly. Can anyone help with info
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Joined: Mar 2008
Posts: 207
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ML320CDI 2008 all options inc air suspension
Possibly a bad ground...I'd say the best thing to do is go to the dealer and have it sorted out.From years of towing exp I have found that bad ground connecctions can do the craziest things. I think the MB harness is preassembled and plug and play on the line so the wrong conections are unlikely but perhaps a break or flaw in the wire is a possibility.Hopefully they will give you an S-class for a loaner while its being sorted out....lol
Thread Starter
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Joined: Sep 2006
Posts: 156
Likes: 10
Thank you, I went to the dealer today, SA of course never heard of such a thing, he called the shop forman and he has seen or heard of this, although never in person. S.A. did say not to bring the car in until they find something out in advance.
