The side markers and tail lights share the same circuit and wiring on the trailer.
The actual brake lights are a separate circuit and wiring.
Does all of the trailer lighting work when it's hooked to the Xterra?
Get a test light or multi-meter and do some testing at the plug on the truck. Google the wiring diagrams for a standard 7 pin plug and see if you have 12v on the pin that is for the tail and side markers. Turn the parking lights on to test. Remember you'll have one pin that is 12v constant hot, so don't get it confused with the tail/side markers.
Work your way either forward or backwards depending on what you find. If you have power at the plug on the truck, then look at the trailer wiring and plug. If no power on the truck plug, work your way forward.
It's a process of elimination and likely a very simple solution.
Be sure you have a sold ground on the trailer to the truck. A flakey ground can cause all kinds of odd problems.
The actual brake lights are a separate circuit and wiring.
Does all of the trailer lighting work when it's hooked to the Xterra?
Get a test light or multi-meter and do some testing at the plug on the truck. Google the wiring diagrams for a standard 7 pin plug and see if you have 12v on the pin that is for the tail and side markers. Turn the parking lights on to test. Remember you'll have one pin that is 12v constant hot, so don't get it confused with the tail/side markers.
Work your way either forward or backwards depending on what you find. If you have power at the plug on the truck, then look at the trailer wiring and plug. If no power on the truck plug, work your way forward.
It's a process of elimination and likely a very simple solution.
Be sure you have a sold ground on the trailer to the truck. A flakey ground can cause all kinds of odd problems.
