I get the blue wire is for the actual brakes on trailer. White is ground. Red is for the brake switch which makes the brake lights work and in the controllers case it gets the signal brakes are being applied. And black is the power wire. Where I'm unsure is if I need anything else or can I just wire it straight up and be fine with my older truck. Alot of stuff that confuses me is with the newer vehicles requiring this or that as well for the brakes to work. And they don't say anything about older vehicles. Lucky for me my suburban had the wiring harness already wired so i just had to get a controller and plug the harness in.
