I have a 99 civic ex1.8L. When it was purchased the factory stereo had been replaced with an aftermarket. I found that the instrument lights did not work. I checked to see if an after market harness was used for the installation of the stereo and it was not. The wiring harness plug has been cut off and the wires have been spliced to the new stereo. The factory stereo is not with the car.
I have been told that if the factory radio is removed the interior light and the instrument lights will not work.
My question is what wires do I need to reconnect to make the instrument lights work and what are the colors of the wires I need to reconnect.

 

The circuit diagrams in the manual don't support the idea of a requirement for the stock radio for either the interior or instrument panel lights to work.

First check whether fuses 30 and 43 are blown.

Next check whether the dome light switch and dash lights brightness controller are bad.