hey guys im intalling an aftermarket unit and it has a orange wire that in the book says connect to light switch.

i am assuming that means dimmer switch

but my question is... i have a stock dimmer wire and a illumination wire.

so whats the difference?

on aftermarket radios I have dealt with and installed which is well over 100 I have never used one of those wires. On my 88 Sport Coupe I believe its an orange wire (cant remember). They are the same if my memory serves me.

i dont think i used mine either, hmmm now im curious

The Illumination wire puts out +12v anytime your gauges are lit up (when the running lights or headlights are on) regardless of the brightness level you turn the headlight **** to. The Dimmer wire puts out between 0v and +12v depending on the brightness you have the headlight **** turned to. This allows the radio to dim with the rest of the indicator lights. You don't need to connect it, but you might as well, it's just one more wire. I would connect to the dimmer one, although the aftermarket radios I've installed are either completely dim or completely bright, so it doesn't really make a difference. Might as well connect to the one that MIGHT give more functionality then the one that definitely won't. The units I've installed also have an option to turn of the headlight controlled dimming and allow you to override it so there's really no point not to hook it up.

It is especially nice if you have a unit that's all a touch screen because they will be very bright at night or very dim during the day and need constant adjusting in the settings. If you have the dimmer wire hooked up as soon as you turn on your headlights the radio dims and you don't have a bright monitor shining right at you when you're driving.