There are two light positions in the bottom of the speedometer, and two in the bottom of the fuel gauge. The "4WD LOCK" film should be for one of the two light positions in the instrument cluster basket behind the speedometer. They shine through a hole in the speedometer gauge face. I think it's the left one of the two on mine, but if you shine a flashlight from the firewall against the back of the instrument cluster basket on the speedo side, you should be able to see it light up. The bulb holder on the end of the 4WD switch pigtail plugs into the back of the basket in that position and locks in with 1/4 turn.