No trailer tail lights!!

Ok, hooked up the trailer tonight to prepare for tomorrow's trip. Brake and both turn signal lights work fine on the trailer, but the tail lights do not. I checked the plug, and the issue lies with the truck. I am using the Hoppy 7 round/4 flat combo harness wired directly to the factory plug. I have pulled the trailer multiple times previously with no problems.

The #30 fuse is good, and I can hear the relay in the back clicking when I turn on the parking lights, but no dice. If the ground was poor, none of the lights would work, correct?

I don't have my tools w/ me, so I can't pull the aux relay box out and swap relays to check that, I'll try it tomorrow when I get there. Would the relay be clicking if it was bad?

Thanks

Edit: 99 Eddie Bauer 5.0L

 

[rookieshooter]

One my untility trailer when the ground is not connecting right in the plug. Some lights work and some don't. On mine it's the running lights. When I wiggle the connection where the ground is, all the lights work. I'd check out the ground at the plug and at any points along the frame where the ground could connect.