a little info is needed. what column? and what turn signal switch? does it have hazard flasher function? half ton or bigger? don't be pulling wires out of the wire loom yet, chances are the wiring is fine.
first thing is to check grounds, a bad or partial ground will just pop-up and cause headaches. do you have led replacement bulbs or led lights with 2 wires.
other than the same housing, the tail light and stop/turn light are separate. tail lights and front running lights get power from the headlight switch. stop/turn lights are the same circuit and get power thru the turn signal switch.
the turn signal bulb is the same as the stop light bulb. same bulb, same wire.
stop/turn wiring is simple, 7 wires: 3 hot in (turn flasher, hazard flasher and brake switch) and 4 wires out to each corner of the truck. the turn signal switch is the confusing part, cuz it combines the brake power and the turn flasher power, depending on what your using
this is an early bronco turn signal wiring and switch. very typical of any pre computer car with hazard flasher, this is what ez wire will look like. i chose this cuz it shows the internal function of the switch. if your truck has signal-stat it will be the same. take a long look at how the turn signal switch runs power thru to each corner.
get some answers and report back