2014.5 Interstate. Blinking lights

[AirHog]

We are confused. Just hooked up our motorcycle trailer to the Interstate. Except for running lights (head light, or side light)- all the trailer lights is functioning properly. Turn signal, hazard, brake, reverse lights goes on and off as intended. However, no running lights, but every 5 seconds all the lights blinks. The trailer lights are fine as we tested them on another vehicle. Sprayed the electrical cleaners on the wiring harness and the light receiver. Nothing. The running lights on the trailer, however it blinks every 5 second. The wife says the trailer will look like a Christmas tree while driving in the dark. I hope this is not normal.

Help.

[AirHog]

Looking for help

[Ron_CA]

Did you look in the manual under trailering?

I was thinking maybe turning off the traction control?

[Boxster1971]

If those lights are LED that is your problem. The Sprinter trailer light circuits don't work well with LED lights.


- - Mike
2013 Interstate Lounge EXT on 2012 Sprinter

[clarklaflare]

Originally Posted by Boxster1971

If those lights are LED that is your problem. The Sprinter trailer light circuits don't work well with LED lights.


- - Mike
2013 Interstate Lounge EXT on 2012 Sprinter

I tow a number of trailers with my 2013 Sprinter 3500, all of which are equipped with a full compliment of LED lights. When I first started setting up my van, I ran across a number of comments in various Sprinter forums about compatibility with trailer LEDs. Near as I can determine, Mercedes must have addressed the problem beginning with the 2013 MY vans because I've never had a problem with any of my trailers.

[Boxster1971]

The LED lights on my rear carrier worked, but they did a few weird things. With the Sprinter turned off they stayed very dimly lit. While driving activating the brakes caused the stoplights on the carrier to flash. They also flashed with each turn signal. So the were OK, just unusual.


- - Mike
2013 Interstate Lounge EXT on 2012 Sprinter

[joemikeb]

When I was shopping for tow dollies I was told by several manufacturers the light circuits on the 2013 and earlier Sprinter models always have a small current "bleed" through them. Apparently this was a common practice in other German made vehicles such as BMW and VW as well. I suspect it was/is used to identify when an exterior bulb has burned out. The current bleed is not enough to make incandescent bulbs glow, but LEDs will — dimly. When Mercedes switched to LED vehicle lighting in 2014(?) they changed the system to eliminate the current bleed.

One manufacturer of tow dollies recommended adding a resistor to the trailer light circuit to reduce the bleed current to a level insufficient to trigger the LED lights, but all the others who responded to my queries either offered to install incandescent lighting at the factory or told me I could change them out myself. I ended up buying a tow dolly with incandescent lights.