[JRRKAR]

For you electrical people out there, here's a riddle for you:

I have a 4' pigtail extension (7 prong) for our truck. I need to use the extensions on my father-in-laws trailer since I have a custom bumper and his wiring lead doesn't reach. Last year I was using his trailer and the pigtail wire between the truck and trailer got loose and rubbed on the roadway. Needless to say it burned through the other layer of coating and broke a few wires. I then cut out the bad section and spliced everything back together. This is a stock trailer wire so you had all individual colors and couldn't hook up the wrong ends together (i guess you could if you were color blind). When I hooked up the pigtail back to the trailer, I am getting a short somewhere (i.e. turn on the running lamps and the brake light goes off, etc.) I figured something must have gotten fried on either of the two pigtail end connections. So I just did a continuity check from end to end, and everything checked out fine (i.e. no shorts anywhere). However when I try it on the trailer I still get the same issue. So my dilemma is how can the ends of the pigtail test fine, but yet I still have a short in the wiring somewhere?

I tried the wire with two different trailers and I get the same result. I know it is not the truck because our horse trailer is fine. I'm planning to make up another pigtail but I am really confused as to what is going on.

Any suggestions to try? I like a good riddle but this one has me stumped.

 

[74novaguy]

Try switching your running lights and brake light wire on one end of the pig tail. it sounds like the running lights are powering the brake lights and the brake lights are powering the running lights.

 

[JRRKAR]

I can try it, but the two ends were factory. All I did was cut out a piece in the middle, and re-splice the wires (i.e. brown-brown, yellow-yellow, etc.). I thought that maybe something shorted in the wiring between where I spliced it and the end...but that would not explain why the continuity would still be fine when I checked the ends.