I'm still leaning toward a insufficient ground connection as being the cause of the problem you're describing. To confirm it, you'll need length of wire long enough to reach from your ground connection on the trailer tongue to the negative battery terminal on the vehicle. If connecting the wire to the wire to the negative battery terminal fixes the problem, you've pretty much confirmed a poor ground as being the issue.
I'd also check the spot on the tow vehicle where the # C56175 grounds.... view full answer...
The Roadmaster base plate kit # 118-1 should mount on your 1994 Geo Tracker so that you have a distance between the two front braces of 28-1/2-inches (with a 1/2-inch tolerance). The instructions (linked for reference) note this dimension and also to leave all fasteners loose after initial installation to allow for final adjustment and positioning before applying the final torque. Since the vehicle's front frame crossover tube is used for this installation you might try loosening the fasteners... view full answer...
You will want to verify that both brake light signals are working at the RV side trailer connector. Unplug the Peterson Magnetic Tow Lights # PE26UR, and use a circuit tester such as # PTW2992 to test the pins on the 4-Way while someone sits in the RV and runs through the lighting functions.
The most likely cause of this is a bad ground or dirt/corrosion in the trailer connector on the RV. It would take a very small wire brush or small screwdriver to clean on the 4-Way. This recently... view full answer...
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