I'm having the same problem/s. 3rd light works, turn signals, running lights all work and hazard lights also work. Replaced the switch didn't work, 2 other time it did work. Checked fuses, the 10amp inside cab was blown but didn't fix problem when replaced. Pulled relay, check ground (lower right plug) - good. Check hot (lower left plug) - good. Applied braking and checked hot coming from switch (top left plug) - not power. Applied a jumper from lower left plug to top left plug with relay partially installed and lights worked. So seems no power coming from switch to relay. But must have power to switch because 3rd light works when pedal is pressed. I didn't know the brake lights went through cruise control but I will try CC tomorrow to see if it works. Also while hazard lights are on, brake pedal does not stop them from flashing.