most tf trucks i've owned had the signal-stat 900 turn switch, it looks like an add-on but isn't
only 1 truck had the built-in switch in the column
turn/brake wiring can be confusing, in the pre-internet days all i had was a motors manual, it was worthless
the biggest thing to remember is that
your brake lights are your turn signals
6 wires: 2 are hot in, the other 4 go to each corner of your truck
one hot is from the flasher, the other hot in is from the brake light switch
there is no other wire coming off the brake light switch, only to the turn signal switch
tail lights and front running lights come off the headlight switch
modern turn signals wiring is 7 wire, cuz they break out the turn flasher and hazard flasher
any aftermarket wiring harness is 7 wire, if you look closely blue and yellow are combined in the signal-stat 900
to add to the confusion, our trucks have no fuse panel from the factory
both brake/turn and tail/running lights get power from the headlight switch
orange text brake & turn is the feed to the brake light switch and thus into the turn signal switch
black text is tail lights and wires directly to the tail lights
purple text is front running lights, they turn off when headlights are on
on a new wiring harness you will have a separate fuse for turn flasher and hazard flasher
you would not wire these from the headlight switch
i did a write-up on the headlight switch and how it is used as the main fuse box on most trucks a few years ago here
http://67-72chevytrucks.com/vboard/s...71&postcount=7