Originally Posted by JBert
For LED setup?
The socket has 3 wires. A ground, a +12v running, and a +12v brake. It doesn't matter if the bulb is incandescent or LED. One incoming wire tells one filament to light, and another wire tells the other, more brighter filament to light. The same two wires tell the LED to come on at a certain brightness, and the other wire tells the LED to get brighter. The principals are the same and require the same troubleshooting steps regardless of the bulb technology