I have a '03 quad cab 2500 with a cummins. When I push the brake pedal, there is a delay of about 3 seconds before the brake lights come on. At first i thought the trailer brake controller was connected wrong, but unplugging the pigtail doesn't make any difference. Fuses are all fine, wiring all appears to be fine. I've only had the truck for a month, but didn't realize the light issue until backing a trailer in the dark. (occurs with or without trailer connected) third brake light doesn't work at all, no power to it, but plenty to the cargo lamps. Any ideas?

 

nevermind, one of the wires on the brake switch had been cut to add a brake controller, instead of using the pig tail stuffed in the glove box. the cut wire kept the CHMSL, or third brake light, from working. basically the same thing as a blown fuse.