Sprinter Navion trailer power socket question

[spinnin4s]

I have a 2017 Navion 24V and want to flat tow my '06 Scion. With the ignition switch ON and activate either the left or right turns signal, I do not measure any voltage on any of the 7 pins on the rear trailer power socket-with exception of the 12V power pin. My voltmeter ground is connected to the chassis frame. Also there apparently is a 'Trailer Recognition Unit' installed in my Navion-how does it work, where is it located, and would it have something to do with not observing any turn signal voltage on the trailer power unit?
Thanks in advance!

[luvlabs]

The trailer brake signals go through the CANBUS system in the Sprinter. There is no voltage supplied until a resistance is measured on the line. So, you can't check at the trailer connector with a multi-meter or a LED check light but a good old light bulb test light will work fine. Just another weird Mercedes quirk. BTW, you can't really use the 12V line for much of anything either.

Wire your car up, add the diodes as needed, and plug into the Navion. It should work fine. I used a Tow Daddy system (bought out by Hopkins) to wire up my Honda Fit and it works fine with the Mercedes CANBUS.

[spinnin4s]

Thanks very much for the information. Do you happen to know what CANBUS stands for, and perhaps where I could find a wiring diagram for my 2017 Navion that shows the trailer power socket?
Thanks again.

[luvlabs]

No clue on CANBUS but I suppose you could ask a Mercedes mechanic if you run into one. Believe it or not, the wiring diagram for your trailer plug is molded into the plug cover. If that is too hard to read, Google "7 way trailer plug" and you will get all the information there is to be had.

[TriGlider]

Originally Posted by spinnin4s

Thanks very much for the information. Do you happen to know what CANBUS stands for, and perhaps where I could find a wiring diagram for my 2017 Navion that shows the trailer power socket?

Thanks again.

Here ya go. This is from my 2016 Navion manual.

[nehog]

Originally Posted by spinnin4s

Do you happen to know what CANBUS stands for,
Thanks again.

CANbus
A Controller Area Network is a robust vehicle bus standard designed to allow microcontrollers and devices to communicate with each other in applications without a host computer. It is a message-based protocol, designed originally for multiplex electrical wiring within automobiles, but is also used in many other contexts.