Never used factory light harness not working, Trailer lights ok

Hey all, I recently picked up a small travel trailer and when we hooked it up the trailer lights didn't work. We double checked with a different truck and confirmed that the trailer lights are functioning. It is the three prong harness and the one on my truck from the factory was zip tied to the frame. The fuses all seem to be good. Anyone else had this happen? If it was never used before is there a logical reason it would not be getting power to the trailer?

Thanks for any help or suggestions!

 

Do you have a Volt Ohm meter? Trace the connections. If you don’t have a VOM then its hit or miss, clean the connections/contacts, try it again.

 

We used a light tester to check the fuse panel and relay under the hood. All was good. Not getting anything at the trailer connection. Are there any other connections to check?

 

Ground? And why was it zip tied? That leads me to think something major happened to it

 

I don't think a zip tie was Toyotas approved method of equipment installation.

 

Do you have a aftermarket hitch on the truck?
Maybe someone installed a hitch and wiring aftermarket and a splice is loose.