hitch wiring malfunction

I have a 98 Blazer 2dr 4wd and have had a trailer harness connected since i bought it. I have regularly towed a boat and now i have lost connection somewhere for my right turn signal and brake. all of the lights work on the truck I just don't have power to the harness anymore for the right(passenger) lights. taillights are normal on the truck and trailer and the left trun and brake work properly. I have traced the wires to a 4-way in the harness located behind the rear bumber next to the gas tank. I still do not have power in the wire there. I am hoping that someone could help me with where the wires go from there. Are the trailer wires joined off of the taillights at the back or do htey splice in somewhere else. where should i be looking to locate the problem. If i remove the taillight on the passenger side will i find a wire that leads to the trailer harness. Help please!!!!!

Clean the connector with contact cleaner to get rid of any corrosion.

Make sure the wires are firmly inserted into the connectors.

Did all that earlier... Found that it was a fuse, I did not realize that it is all seperate fuses for each light.

Good to hear you found your problem