Sydwayz

iTrader: (1)

Has anyone messed with this before?
We brought home a 2010 Mercedes Benz M-Class ML 350 BlueTec (diesel) a couple weeks back for my GF. She wants to tow her small vintage camper with it, rather than using one of my trucks.

I've got the hitch setup all taken care of.

But the problem is with the Trailer Wiring. The only thing that is right in the connector on the back of the SUV, is the Common Ground.
I've checked all of the fuses. There are no missing fuses regarding the trailer wiring. I've checked the manual, and it doesn't really talk about anything here.

I've seen some references online, and there may or may not be a reprograming that is needed by the dealer to enable the electrical system for towing.
Does anyone have any insight on these vehicles?

blaquebaja

Check with uhaul they should know how hook up your lights

Sydwayz

iTrader: (1)

Thanks. But at best, UHaul will only be able to get a 4-wire flat connection working at that is all their trailers have; and I highly doubt they will want to touch this vehicle.

F-2 Speedy

iTrader: (6)

whats the issue ?? you don't know what pin does what ? looks like right turn, left turn and brake to me, don't know what 4 vdc is used for, maybe electric assist.

Sydwayz

iTrader: (1)

My apologies for not specifying. Those are constant voltages at the vehicle side connector as soon as the ignition is turned on.

the bear

Never had the opportunity to use the mercedes but etrailer.com sells adapters that will plug in to that configuration and change it too what ever you need.

F-2 Speedy

iTrader: (6)

but does the voltage go away after its started

Sydwayz

iTrader: (1)

No, those voltages stay at constant, no matter engine on/off, ignition on/off.

This is what they are supposed to be doing:
[ATTACH=CONFIG]556128[/ATTACH]


Now, there are two different wiring configurations for 7-way plugs. Regardless, this isn't likened to any of them.

F-2 Speedy

iTrader: (6)

how will anything work correctly if all the pins are constantly hot............ I see your issue........
kind a crazy, frickin Germans LOL

VoodooRob

We had run into a similar issue with a Porsche Cayenne Diesel. Ended up taking to the dealer, they hooked up their fancy Porsche Service computer pressed some buttons and all of the sudden trailer lights worked. This was for a 4 way plug on a SeaDoo trailer. We were using a 4 wire adapter and thought that was causing us grief, but it turned out to be programming in the vehicle.