Hi Chief2,
Sorry to hear you're having this problem. I would start by getting a 12v power source (a spare battery will work) and unhooking the trailer. Run one jumper wire from the positive terminal and one from the negative terminal of the battery. Touch the negative wire to the white wire pin in the trailer's pigtail. Now touch the positive wire to the yellow wire pin in the pigtail. Left blinker light should come on, but will not blink. Now touch the positive wire to the green wire pin in the pigtail. Right blinker light should come on, but will not blink. Continue touching the positive wire to the remaining pins in the pigtail, verifying that all lights are functioning properly. If they do, the next thing I would check is your ground. Sometimes if you have a weak ground, the current will flow through other lights that aren't even turned on because it "jumps" across the bulb. Even L.E.D.s can do this. Sometimes you'll have just enough of a ground to operate one light properly, but not all of them. Electrical current looks for the path of least resistance, just like water. Find your ground and unscrew it. Clean all contact surfaces thoroughly, and then smear a little dielectric grease on the connection. Reattach the ground screw and test all lights again, this time using the pigtail connector from the vehicle. If you do not have a direct ground wire, and are grounding through the hitch/coupling itself, then that is definitely the problem. You'll want to add a dedicated ground wire if you don't already have one. Good luck.
