View Full Version : Right tail light/trailer lights

01-20-2013, 10:46 PM
2003 2500, The right tail light and the tail lights for the trailer hitch don't work. The trailer lights were a dealer installed Sprinter accessory with the trailer hitch so there is a single wire harness from the hitch to under the drivers seat. All trailer lighting functions, except the tail lights, work in the module under the seat. I don't see where there is any other wiring connection for the trailer hook up, but there must be some connection between the right tail light and the trailer. Any suggestions? Thanks

01-21-2013, 12:16 AM
I can't find the dealer installation manual for the trailer connection at the moment (there are many postings of it in the group), but i think there's a "module" (diodes and stuff) dropped into the left (driver's side) rear pillar.
In other words, remove the Left taillight assembly, and look down through the (now) empty hole.
The module's wires are spliced into/onto the left lamp assembly's cable.


01-21-2013, 05:53 PM
I took the left rear tail light assembly off and there is no module. The module is under the driver seat and all lighting functions for the trailer work there except the tail lights. It looks like there was possibly a splice under the van below the left rear lights. I hesitate to cut that mess open but I don't see anywhere else that the trailer lights and right rear light could have a connection. I searched the write ups for trailer lights and didn't find the dealer oem procedure. Thanks, it helped me narrow it down maybe.

01-22-2013, 03:11 PM
After finding the 2001-2006 VA Sprinter Body Electrical pdf in this forum, it looks like the taillight function is not part of the control module under the drivers seat. That leads me to believe that the taillight function is a simple splice into the harness at the rear of the van and my simplist fix will be to run a wire from the left taillight to the right taillight and connect the trailer light to it. Since it isn't addressed by the oem module, I believe this will repair my taillight problem and not cause an issue with the vehicle computer? Thanks

Aqua Puttana
01-22-2013, 03:33 PM
Before you tear into the wiring...

Have you tried twisting the stalk for lights and see if anything shows for lights then? Conversely, if you've been testing with the stalk lights on then see if anything changes with the engine running and DRL's on.

Have you triple checked all fuses? I had a weird running light problem that revealed itself as a blown fuse during some later troubleshooting on another issue. I find the fuse maps vague. Don't just look for the fuses in the map descriptions. Check each and every fuse under the steering column and under the seat.

Sorry I can't offer more. vic

01-22-2013, 03:40 PM
I have been checking voltage with the lights on but not running. I will double check all the fuses. Doesn't seem like there wouldn't be different fuses for the left and right taillight, but it is a German creation. Thanks

01-22-2013, 07:31 PM
OK, so after tearing the van apart: seats, taillights, wiring, etc., and spending hours researching wiring, etc., it turned out to be fuse #1 under the steering column for the right rear taillight. I honestly don't know if anyone who has worked on American vehicles for 50 years will ever be able to work on European vehicles. They are too weird. Thanks to everyone who replied, especially Aqua Puttana, who slowed me down before it became even worse.

Aqua Puttana
01-22-2013, 08:53 PM
...I honestly don't know if anyone who has worked on American vehicles for 50 years will ever be able to work on European vehicles. They are too weird. ...
I hear ya'.

In this case the FB#1 position #1 Fuse is clearly marked "Parking lamp, taillamp right". Then look at #11. "Side lamp left, tail lamp left". So where did the "Parking Lamp" go for the left side or the "Side lamp" go for the right? They are not very consistent.

To make it more confusing when my #11 fuse was out the left running lights (taillamp) would work when on DRL, but would not turn on with the engine not running and stalk switch twisted to on. So I know that there is another feed to the left running lights, but I haven't found it identified on my fuse maps. Probably just one of the "Daytime Driving Light" positions in FB #2. :idunno:


FB #2 is bad with all the "Daytime Driving Lights" fuse and relay labels. "Daytime Driving Lights" where? (Positions #2, 5, 10, 11.) I know that they can be traced in a schematic, but maybe a bit more than "DRL" alone would help some.



At least we gain knowledge here as these problems are posted and people follow up with their resolution. Sorry to go on. Thanks for the feedback. :thumbup::thumbup: vic

01-22-2013, 08:59 PM
Thanks again, older Ducatis when the taillight burned out, the bike would just die and not start, so I guess it could be worse! Now to start on my leaking water pump. Larry H