Trailer Light question

[decksweeper]

These things might be the most frustrating thing to change IMO....Bought some new submersable LED lights....as always, had trouble with the ground but finally figured it out. Here's the issue. The lights work perfectly on my dads truck, but when I plug it into my Jeep, neither the brake light, or directional works on the passenger side. There's power getting to the passenger light because it works when I put my headlights on. My harness is brand new? Anybody know why it wouldn't work on mine, but it does work on my dads?

thanks in advance..

Mark