2003 eclipse dash light problem

Hellow everyone, I have been having a problem with my car for about 2 months now and cant seem to figure out the problem on my own. I have a 2003 mitsubishi eclipse and the backlight on my dash works when it wants to it seems like. I can be driving for 5 min then suddenly it will turn off and all that is on is the dial for the guage lights up but nothing else on it. But then other times it wont turn on when i turn the car on and then maybe 20 min later it will sudenly turn on by itself. The car also has an aftermarket color changer and dimmer switch for the light. I have checked the fuse and the cords for the switches and the dash and they both look fine so they dont seem to be the problem. Hopefully someone can enlighten me on my problem so i dont have to spend alot of money for a mechanic to look at it and fix it.
thanks pj