3rd Brake Light Wiring

Can anyone tell me the Voltage going to the 3rd brake light? I want to splice an LED strip into the 3rd brake light and illuminate it when the 3rd brake light does.

Any help greatly appreciated.

Chris

what make, year model of car? If it is just a bulb then it is 12 volts

I don't know of a single car that doesn't supply 12v to the brake light. Some step it down in voltage once it gets there for LEDs, but as far as I know they all supply 12v to it.