On my 2006 Honda Element, I installed an aftermarket (Kennwood)radio. Now, my lights the odometer and instrument cluster is out. THe MPH, Tach, and Fuel gauges light up but not the backlight. All bulbs are good and not burnt out.

 

fuses. I'm gonna take a wild guess and say you DID NOT connect/properly terminate the ORANGE ILLUMINATION wire from the factory wire harness to the headunit. That has +12VDC when you turn on the lights. If you left it exposed, the wire eventually touched ground and shorted out a fuse. This happens all the time.

 

NVturbo's scenario is the most likely.

Pull the radio and cap off the illuminati wire on the harness.
After doing that replace the blown fuse in the fusebox and you should be good to go.