Trailer Backup Lamp Connection

We have a 2008 Sprinter with the factory 7-pin trailer connection. Pin 7 is labeled "Backup Lamps". The pin is wired, but does not provide current for the trailer backup lamps when the van is in reverse with its own backup lamps lit. I know that there is continuity to the pin, because there is a 12.9 volt potential whenever the ignition key is on. However, there is not enough current to light the small incandescent lamp in a circuit tester.

The turn signal and running light pins also have the same low-current 12.9 volts present with the ignition on and those lamps off. All other pins work as expected.

Any thoughts on the cause and solution? Does anyone have trailer backup lamps that work with a recent model Sprinter?

Thanks!

- Gene

None of the trailers that I have used have backup lights. Maybe that is why the wire is not connected. I wouldn't worry about it. I learned this from my time driving a tractor trailer, a long time ago, which none have backup lights on the trailer. Put the 4 way flashers on and back up slowly.

Thanks for the response. Let me clarify the situation:

My trailer does have backup lights. I also have a wireless backup camera for the trailer, which is powered by the backup light circuit.

I want to use the lights and camera with the Sprinter.

- Gene

I see.