Pull the clips off if on. slide the barell into hole reach under and push clips up against dash. The clips hold it tight. The wiring spade is for ground if your dash is not allready grounded (metal dashes are usually grounded already. The spade is more commonly use for plastic dashes and you ground it to a metal brace.
Been a long time since I installed one they use to come with a red or black lead and ground.
popcorn The Truth is Out There (Really its been a long time)
