Hood Mounted blinker

The screw is the ground. The amber part in your picture just pushes down and there is a bayonet style bulb underneath. I had to run a tiny bead of solder on the copper portion of the assembly to make sure contact to ground was made when the screw was installed. Worked like a champ. For some reason you need the ground here to have working brake lites. BTW, it helps to pull on the bulb with tight fitting piece of vacuum hose, just slide it over the bulb and lightly squeeze while pulling the bulb upward. Good luck.