My wife have a 2002 F-350 and my trailer tow wiring plug and wires harness was in sad shape.
What is the BEST replacement?

 

It truly depends on what "plug" means. The oem will be simple plug and play, that beats splicing almost always. Hard to give better advise on a 22 year old truck that might have been hacked another time by others.

 

To be honest…pick something off the rack. Especially it’s plug and play.

I sincerely doubt Ford does anything other than outsource this stuff to the vendors you will stare at in the towing section at your favorite parts store, anyway.