The radio is the Delco AM/FM/CD model that appeared in many GM models anywhere from 1996 - 2002. The buttons and labels on the faceplate are backlit with a number of 12V incandescent bulbs. I initially set out to do a direct replacement of the bulb on the circuit board. In the end, the implementation was a little different. Due to the space constraints, right away I knew I would need to find an LED with an integrated resistor. They do exist, but they are quite expensive and I could not find any in blue. So at this point the best thing to do was to remove the incandescent bulbs and glue the LEDs into the faceplate, creating wire leads to solder to the circuit board.
Step 1: Disassembly
The first image shows the front of the circuit board. The second image is the back of the faceplate where the circuit board connects to.
Step 2: LED Placement
I installed the LEDs in the faceplate, routing the wires as tightly as possible and keeping the power and ground wires together. The faceplate is a very tight fit to the circuit board so routing the wires efficiently is very important. A single pair of wires connects the power and ground to the circuit board in the place where one of the incandescent bulbs was. The picture is showing the LED grouping and placement. Much more work was done later to get the wires routed tightly. The blue LEDs and wires were glued in using some silcone glue.
Step 3: Installation
I've got more pictures and details on my site at:
I also have info on how I added a blinking security light.