High top brake light for 1985 GMC conversion van

The two wires (Red/Black} register 11.41 Volts when they are not connected to the light and the brake pedal is depressed… when the light is connected, it dosen’t burn… it burns when connected to the battery directly… Plus the two wires don’t short out when touched together when the voltage is present… Any ideas???

Check to see if the bulb is installed correctly. In spite of being designed to only go in one way, some bulbs are easy to install incorrectly.