Why don't my illumination dash work any more?

All the lights on the dash work except the ones that light up the gauges so you can see them. I dont know what is wrong. I installed an aftermarket cd player and evarything was working fine still. Then one day I noticed that when I turn off the van that my stereo would stay on until the lights went off. A few days after that my illumination lights quit working. Then I looked at the wires on the back of my cd player and I had the dimmer wire hooked up to the power wire, so I unhooked the dimmer wire from power wire and taped it off not hooked to anything, but that didn't help the dash lights any. I pulled out the instrument cluster to check the bulbs. I found four of the illumination bulbs were burnt out. I replaced the bulbs and put the dash back together and still nothing. I have checked all the fuses and they were all good. Now I don't know what to do next.