Ed W posted:The bulb is dark, not doing anything.
This accessory is heavy reworked. I would start by just trying to get the bulb to light. As shown below there is supposed to be one wire that goes to the bulb. The other connection is to the chassis. Verify you can get the bulb to light. Connect one power lead to the chassis and the other power lead to the wire going to the bulb and the light should illuminate.