Alarm light on dash
If so, there is constant 12v power on one side of the socket already. All you have to do is make the ground on the other side to get a lamp to work there. I used a self flashing LED but the concept is the same. The connector has a blank spot for the ground wire. If you can find an electronic parts store and purchase the correct MOLEX terminal, then all you have to do it solder it on and shove it into that connector and then run the wire to your switch or whatever you are doing to get that to light.
Here is a progress photo when I was installing an LED in that spot. I later cut the leads after I soldered them to the circuit board. Sorry I don't have a picture of the finished work.

Actual credit goes to SpringerPop for the research to figure this out. I just followed his lead...
Lots of great info here on FTE.




