Installed Brake Controller
I bought a Tekonshsha P3 and started searching for the wiring on our 2004 Gulfstream Crescendo. After searching for more time than I care to admit under the dash in 97 degree temps, I found a wire loom under the dash all the way to the left that appeared empty, but peeling back the loom, saw that it contained 4 wires each marked on the insulation as to which they were (trailer brake, stop lamp, etc...). Each had a mini-bullet connector on it. I just cut off those and crimped butt connectors to the Tekonsha harness. Worked like a champ.
Thought you might want to know. It took me longer to find the wires than to do the entire install/test.