I tried searching but couldn't come up with anything similar to my issue either here or on the google.
So I recently got this trailer wiring harness: http://www.amazon.com/gp/product/B00...?ie=UTF8&psc=1
Got it installed and all seems well, I tested each function (minus brake lights since I have no helper up here to hit the pedal) with a multimeter. My lights were all sorts of jacked up on my jet ski trailer as well so I installed all new lights. I plugged them into the taco and all I could get was extremely dim hazard lights. Sanded all the grounds clean and tested them with my multimeter for continuity between the wire and the frame so all is good there. I tried powering each of the 4 wires on the trailer side with a battery and everything on the trailer worked fine.
So I am stumped. I appear to have voltage from the truck, and all the trailer lights function when powered directly with a 12v battery. Anyone ever seen this before? I can't think of what it could possibly be. I have another trailer across town that had lights last time I pulled it so I'd like to get over there at some point soon to test it to see if it still works. I'm open to any suggestions