Camper wire harness - suddenly lost taillights

[alvald83]

I have had my cabover camper on my truck for a year with all the lights working properly. I am now in the process of adding a 2nd battery using a Stinger battery isolater relay. Today, while digging around under the dash to look for a hot wire and taking a look at my camper wire connections, i seem to have messed something up. I have no tail lights on my camper now.
I am using my stock camper 6 wire wire harness (which has been working). After testing the harness i discovered that the black wire which was used for my rear taillights is not working. I tested the other wires (brake,signals,camper interior lights), and all are working properly.
The only thing that i could have messed up on, is that while digging around with my test light and using it on my unused dual brake warning light, i shorted it on the dash. I did see a few sparks. The fuses on the fuse panel are good. when i turn the lights on my rear lights on my truck go on but not on the camper. Is there another fuse somewhere that i am missing? Hopefully, my explaination didnt confuse you. Thanks for your help.

[1972hiboy]

"After testing the harness i discovered that the black wire which was used for my rear taillights is not working. I tested the other wires (brake,signals,camper interior lights), and all are working properly. "

This statement is a tad confusing. Im going to try to understand. You probed the truck side connection for your camper hookup? You tested for proper signal from the connector that your camper would use? You saw a brake lamp signal and turn sigal for both left and right? ( which use the same wire) and your power in for the interior of the coach is working? Im confused about the black wire your reffering to. in 12vdc systems black insulation typically indicates a Ground. Which would help explain why you werent seeing and power coming from this wire.
Im going to offer a suggestion based on what is here and hopefully it helps. if not maybe you can re-post and we can narrow it down for you. If you are getting the signals you need from the truck then the problem must be from the plug to the camper. I would double check the connections inside the plugs on your harness to make sure one hasnt backed out. Do the left and right signals work on the coach? This is important because the brake lamp and turn signals use the same two wires. if the turn signals work id look at a light bulb in your taillight assemblies. on older coaches, ive seen many times the one tailight gets the signal then the other brake lamp is tied right to it and the wire jumps over the door to the other. If the one filiment goes out for the brake it would stop the other from working to like a old set of christmas lights.