I am a mechanic of 40 years, I have done a lot of automotive electrical over the years. This is a great switch, well built and can handle 30Amp load, which for automotive lighting, generally save having to install a relay to control the larger draw. This is a 4 terminal switch, the duckbill lights up clear when off and red when the switch is on. Which I would think the duckbill lamp should be hooked to Parking lamp feed, or Ignition hot wire so it is not on all the time the truck is not in use. There is No wiring diagram on the bag or switch. I can use a 12v source, or a multi meter and figure this switch out in a few mins. But a lot of people would struggle with this, or damage the switch, etc. Please, Just put a small wiring diagram on the package or switch. Thanks, Mike