Hey, I just spent 4 hours trying to figure out why there is no voltage on the trailer turnsignal and brake light cicuits on my Dodge Ram 1500. It has the factory tow package that includes the 7-pin (and 4-pin) trailer interface. I understand electrical troubleshooting somewhat and have checked all of the connections with a probe starting from the 7-pin connector back to the fuse box. All fuses are good. I even attempted to check the output of the fuse box at the 20-pin connector that appears to feed all of the indicator light circuits. These pins are pretty small and I am not sure which pins are which. Still no voltage on the trailer circuits. All fuses marked trailer lights are fine. There are a number of empty relay sockets but none of these are marked trailer anything. I am stumped. Is it possible these circuits aren't even hooked up at the source?