7 way wiring pin positions

[VAtom]

Hypothetically, let's say someone was having consistent problems with trailer hitch storage box light connectivity. Let's say they changed out 7 to 4 way adapters twice but the problem returned

Then, also hypothetically, let's say they thought they could easily swap out an aftermarket 7-way connector socket with the OEM to solve the problem.

Then further in the the world of hypothesis, let's say it didn't work and perhaps the MB wiring colors were nothing like any standard found for aftermarket parts.

Would anyone on the forum know what the pin positions on the MB 7-way harness socket are?

Top left to right
empty
black with green stripe
white with blue stripe
red with yellow stripe
black with grey/purple stripe

Bottom left to right
empty
black with blue stripe
brown
empty
black with white stripe

The brown wire seems to be the only one that consistently carries current when the acc switch is on.
I also haven't found any fuse related to the 7-way and don't know if there are any OBDII codes that need to be cleared when the socket is replaced.

[Pahaska]

One problem in tracing these wires is that if the Sprinter does not see bulb resistances at the connector, it turns off the signals to the trailer connector.

I ran into this when I tried to power the sending unit for the wireless light bar in my tow car. The right and left turn signal did not work unless the brake pedal happened to be simultaneously depressed. I solved this by buying a 7-way plug that had built-in resistances that simulated bulbs.

I have a hunch that this was your original problem. If you turned on a turn signal and tried to use a meter, you would not get any consistent signals in the 7-way connector.

My wireless transmitter now works great with the loaded plug. I bought the loaded plug from eTrailer on the web.

By the way. When I plug in the loaded plug, I lose the blind-spot sensing in the rear, as well as the backing sensors. Mercedes does this so that the sensors do not see the tow car. I have to remember to remove it when I remove the tow bar.

[Titus]

I bought a 7 way round to 4 wire flat connector at the local big box and it worked fine - so I had no need to figure out the wiring. Apparently MB follows whatever is the standard.

My only beef is that the square box housing the round connector is the low point in the rear. So the box is no longer square - more of a squished trapezoid. I removed the box and wired the adaptor up underneath. Not real convenient but I've only used it once in 4 years and 45,000 miles.

[Protagonist]

Originally Posted by Titus

My only beef is that the square box housing the round connector is the low point in the rear. So the box is no longer square - more of a squished trapezoid.

Mine wasn't actually the low point; because the rear bumper was different in 2011-and-earlier Sprinters. But my 7-pin connector box is a squashed trapezoid, too, because some idiot thought it would make an excellent step and didn't realize it wasn't designed to be load-bearing.

Wire colors may be different on the Sprinter because they're built in Dusseldorf, not Detroit, but the blade positions (it's actually a 7-blade connector, not a 7-pin connector on mine) are still RV standard.

[VAtom]

Originally Posted by Protagonist

Wire colors may be different on the Sprinter because they're built in Dusseldorf, not Detroit, but the blade positions (it's actually a 7-blade connector, not a 7-pin connector on mine) are still RV standard.

I did not know this

"The new (2016) $500 million North Charleston factory expands a current facility where Sprinters are put back together. It’s all about taxes, or more specifically import tariffs. To date, Sprinters sold in the U.S. are first completely manufactured, ready to go, in Germany.

Then, because of the tariffs, U.S.-bound Sprinter are partially disassembled, shipped to the U.S. as components, and then reassembled in South Carolina. That’s been going on since 2006 via warehouse and factory work that’s called “double handling,” and which is seldom efficient and often costly."

OTOH
The "pins" I was asking about are for the MB harness, not the Pollak 7-blade socket. Further research shows it might be the same as the Dodge/Mopar. part

[Pahaska]

Not quite true. Sprinters for Airstream are not disassembled and are shipped intact to Airstream from Germany. Airstream checks all the safety options and gets a suspension option that is not available on Sprinters shipped through Charleston.

The source for this info is an Airstream video.

[Titus]

Wonder if the same will hold true of Interstate-destined Sprinters when the new factory begins real production instead of re-assembly.

What suspension option are you referring to - the air suspension or something else?

[Pahaska]

Originally Posted by Titus

Wonder if the same will hold true of Interstate-destined Sprinters when the new factory begins real production instead of re-assembly.

What suspension option are you referring to - the air suspension or something else?

The cab-chassis may have to come through Charleston. The reason Airstream gets them direct is that they are imported as a passenger van, rather than a cargo van (read Chicken Tax). This is apparently an agreement between Airstream and Mercedes. I have an feeling that the Atlas vans may have to be imported as cargo vans. Note that the Airstream is the only up-fitter that can use the Mercedes star on the rear end.

The video described the suspension as something like "High Gravity Suspension." Apparently only available on passenger vans and not cargo vans.

Wish I had kept a bookmark to that video.

[VAtom]

OK, in the unlikely event that anyone else has a self-inflicted plug-ectomy.