I wired the red(positive) to the grey headlight wire which is the one the instructions in Americanmuscle told me to do. theres a button to dim it which i can press to dim it to almost off (very low dim) im not sure if leaving it like this would be ok.
Well not to sound to harsh but AM is WRONG in your case you need to wire the positive to the BROWN wire that is in the switch. If you have a test light test the wire before you hook it up but it should go to the wire that is hot when you turn the headlights on.
Well if it stopped working already than something is wrong with the product. But the brown wire from your light switch is your parking light wire, witch would turn on your gauges when you turn on your parking lights.