98 Rodeo has no dash lights

We have a 98 Rodeo whose dash lights dont work. We just bought it and immediately replaced the stereo in it, so I don't know if the lack of dash lights are due to the new stereo or if it came this way. I have read various reports from people who replace the stereo and the lights then dont work, but we have checked everything and they still don't work. To install the stereo we used a wiring harness with the illumination wire connected. When the dash lights did not work, we disconnected the orange/orange white wires from the stereo. We then checked all of the fuses: they're all fine. We also completely tore the dash apart to check if the dash is getting power to it: it is. We also checked the dimmer switch, which is fine (yes, we did make sure that turning the dimmer switch doesn't change the dilemma). I have also had a person suggest that the ground may not be making a connection, but we have no idea where the ground would be. Is there anybody out there that can help or suggest something that we may not be thinking of?

Have you tried hitting your dash? No seriously, give it a good hit w/ an open palm. Occasionally my lights go out and a hit turns them back on.