Any help offered here would be appreciated, as Im stumped. I've used the search function with little help. I am refurbishing an old trailer. I bought 2 new tail/brake lights the cheap ones with one bulb and 2 filaments. I am using the typical 4-conductor flat trailer connector. The wiring is as follows one for ground, one for tail (left and right), one for left turn signal/brake, and one for right turn signal/brake. I have cleaned all paint off surface where ground wire bolts to trailer chassis. The tow vehicle is a 88 Ford Ranger. Heres the problem Im having.<br /><br />When I actuate the left or right turn signal, all is well. When I actuate the brakes, all is well. When I turn on the headlights or parking lights, all is well. With the headlights or parking lights on, if I actuate the turn signal in either direction, it flashes correctly. But the taillight on the opposite also flashes, although faintly. I ran an additional ground with jumper cables and no help.<br /><br />To further confuse, I completely disconnected the trailer and repeated the above scenario on just the truck. I noticed the taillight on the opposite side of the blinking light was blinking ever so faintly. This indicates the problem is maybe not with the trailer, but with the truck. All tests were conducted on battery power. I didnt start the engine.
