Hot parking light wire in a 2001

I am hooking up a pair of CATZ Landmaster lights and the fourth wire from the switch needs to be tapped to the parking lights. That is what I want, not trying to tap into another hot wire, but can someone tell me what color wire is the parking lights on a 2001? I found and tried the brown/white wire that I have seen posted on t some sites but that is not it. The brown wire is a live wire that illuminates the switch all the time, afraid it may drain the battery since I don't drive the truck that often. Any suggestions or altermatives?

 

[Timmy]

Look on the holder of the bulb.... I know on the tail lights someone told me to and I looked at it and it said Major, Minor, and Ground if that helps at all.

 

[2001ExpSport]

You tap it from the bulb connector and I believe its the middle wire. Discinnect the bulb and touch the wire to each lead with the lights on. The one that lights them up is the trigger line. Make sure it is not the blicker.