Checked the contacts, they were okay, but changed the line out just the same. Solder connections are and were fine. Pulled the bulbs out of the tail light assy's and the trailer lights worked like they should.
The fuse is 15 amps. It should be a 15 amp fuse based on the wiring diagram as well as the fuse block print.
Only thing I haven't done is get one of them Sunder California special hazard lamp flashers and try that. If their pin config is the same as the flasher, then this may the the solution, or maybe not? grrr....

91 Jeep Wrangler YJ, carpet, tires, trailer hitch. yea....