Struggling to understand what you are trying to do?
When you say:
Cluster, is this the dash?
Hitch, are you adding a tow hitch?
If I guessed right you really should not be messing with the dash loom, all the signals you need to activate relays are local to the tail lights, you will need a power supply from the fuse board - this needs to be fused and when you tap into cables don’t use scotch locks -there is a specific hell for people who use these