Looing for trailer light trouble shooting help

[BigRed118]

Looking for trailer light trouble shooting help

Here's a good one. I have a 16' Charmac enclosed sled trailer. I have installed a battery so that I have lights and power for my furnace. I think that I may have a leak in the roof and I am sealing the whole roof today or tomorrow. I noticed this morning that the right rear tailight(only) is on. The trailer is not hooked up to the truck. I do have a battery charger hooked up. I have had the set up for 4 years or so. So here are my questions. How can my battery backfeed to one light? Is this something to do with the emergency trailer battery? Why would only one light be lit and not all of them? Where do I start to troubleshoot this? Thanks in advance for the help.

 

[snowrodeo]

i hate electrical problems, and im definately no help!
good luck with it

 

[Trashy]

Is it the park lamp or the signal? Because it is only lighting one lamp I would be willing to bet your problem is related to the signal circuit and a ground issue...

 

[BigRed118]

I believe that it is the brake light.

 

[Trashy]

I believe that it is the brake light.

same thing.... they share a bulb and circuit.
lets keep it simple for now, give the park lamp and signal light at that corner a proper ground (a jumper wire is a good way to do this) and tell me what happens...

 

[Trashy]

Did that fix it??

 

[BigRed118]

Wow, that was fun. The ground just changed it from tail light to brake. The weird thing was that the light would work with the ground disconnected. We cleaned the trailer to truck plug and one of the tabs had very little tension to it. Took it apart and it was broken on the back. The emergency brake battery was jumping to the right tail light. Yammy, thanks for your help.

 

[Trashy]

Glad you got er fixed... The light will work without the ground connected 'cause it can still find a ground path thru the park light filament and thus the rest of the park light circuit!