Truck harness or trailer harness issues.
This is a runoff from a previous post I had. I'm not getting brake lights or blinkers on my camper. From a suggestion on my previous post I checked the terminals of the harness on the truck. Yellow wa...
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Keep in mind that the colors on the truck will not match the colors on the trailer. Some do, some do not. You need two color charts, one for TV one for trailer.
According to the Chart Tom posted, assuming it is correct....
You mention some wires jump when brakes or blinkers are on (brake light is the blinker light) then two things could be going on. 1. the voltage for all the trailer wiring is coming from one small source and the extra power demand is robbing power from all others so is making it jump. Unlikely since there is no "demand" given the trailer is not plugged in. 2. a bit of a short, not enough to short and blow a fuse, but just enough to draw down power, maybe a bad ground, or two positive wires touching, barely...
That the green (backup) did anything is an issue, it should only do something with truck in reverse.
I would first assume the wiring is correct, and check for bad wiring instead of wrong wiring.
Is your truck wired with factory trailer wiring or is it spliced into the trucks rear light harness wires?
Your voltage ranged from 12.5 to 13.4, and there really should not be a voltage difference in an open circuit. Seems they should all be 13.4. If you had lights connected then a lower voltage would means one circuit has more draw than the other, but you are not even plugged into the trailer, so I would next assume that the voltage draw is from the truck itself. The truck brake lights would draw more power than the running lights or just one blinker (which is one brake light, not both).
Some trucks have a completely separate circuit for trailer wiring, but some share the circuit with the truck's lights. A shared circuit would make the voltage differences...
Sometimes the easiest way to fix electrical is to start over, run new wires. Tracking down electrical shorts or issues can take 10x longer than just redoing it all from scratch..
According to the Chart Tom posted, assuming it is correct....
You mention some wires jump when brakes or blinkers are on (brake light is the blinker light) then two things could be going on. 1. the voltage for all the trailer wiring is coming from one small source and the extra power demand is robbing power from all others so is making it jump. Unlikely since there is no "demand" given the trailer is not plugged in. 2. a bit of a short, not enough to short and blow a fuse, but just enough to draw down power, maybe a bad ground, or two positive wires touching, barely...
That the green (backup) did anything is an issue, it should only do something with truck in reverse.
I would first assume the wiring is correct, and check for bad wiring instead of wrong wiring.
Is your truck wired with factory trailer wiring or is it spliced into the trucks rear light harness wires?
Your voltage ranged from 12.5 to 13.4, and there really should not be a voltage difference in an open circuit. Seems they should all be 13.4. If you had lights connected then a lower voltage would means one circuit has more draw than the other, but you are not even plugged into the trailer, so I would next assume that the voltage draw is from the truck itself. The truck brake lights would draw more power than the running lights or just one blinker (which is one brake light, not both).
Some trucks have a completely separate circuit for trailer wiring, but some share the circuit with the truck's lights. A shared circuit would make the voltage differences...
Sometimes the easiest way to fix electrical is to start over, run new wires. Tracking down electrical shorts or issues can take 10x longer than just redoing it all from scratch..
