Their is a stock signal wiring diagram on my website http://www.50chevy.freeservers.com/Remote_Entry.html#7%20Wire

Your going to take your brake fused circuit and run that wire into the brake switch and then out of the other terminal of the brake switch up to the signal. You will probably want to use the full-time battery supply of flasher to operated your signal unit "just use your signal flasher in the hazard flasher. The reason for this is because you have a built in hazard flasher and if you run it off the signal side of your harness, you won't be able turn the flashers on without leaving the ignition on. I don't think you'd want to leave the keys in your truck to have the flashers going when/if you leave your truck along side the road if it breaks down.


Joe