Wierd Tail-light problem

[Trunkhill1]

I've rewired the DC connection to the truck with a modern 6-wire plug.  The driver side brake/turn and plate light work as they should.  The passenger side (also a double filament) however will not illuminate the brake when the lights are turned on.  The turn signal flashes at a slightly slower rate than the drivers-side.  I checked out my truck and found my blinkers were functioning normally.  Is there some kind of relay I don't know about?  I checked all over and under the trailer.

[JessEm]

Hi Trunkhill1, Most vehicles have a 'turn signal flasher', usually located in the fuse box. They wear out. I might start there... but maybe someone else has a better idea...



For lack of ANY better explanations, you may need to pull the actual fuse box and look at its connections on the back side... I had the running lights wire arc together with another always-hot wire, and it created all kinds of weird stuff on that circuit. And nobody had been back there since it left the factory.

EDIT: I just realized yours is a travel trailer... I have a motorhome so I'm not really sure if any of this applies.

[legomybago]

Check and make sure your passenger side trailer light filaments are correctly wired. If switched around, or a bulb got shoved in backwards, you won't see any change in brightness due to the bright filament already is lit. Check your grounds.

[JessEm]

I'll second the ground. I was AMAZED when I learned how much... weirdness... can be attributed to a poor ground.

[Rickf1985]

Definitely sounds like a bad ground at the light.

[Froggy1936]

Another very hard thing to find is a bad bulb, That a filament has broken and fallen down to the other circuit . This will drive ya nuts . Best cure replace both dual filament bulbs with new ones Frank

[Trunkhill1]

So after playing with the wiring and wanting to leave it exposed anyway, I gave up trying to fix the OEM assemblies and put in new ones.  They began working as advertised.