Control color of Bi-Color LED using Arduino
You could also do it with minimal components with a suitable dual op-amp configured as two comparators driven by two outputs from the micro.

High on one low on the other would turn on a particular color. Both high or both low would turn it off entirely.







simulate this circuit &ndash; Schematic created using CircuitLab

NOTE: R1 here is assumed to be built into the switch so your LEDs don't fry at 12V. But you need to verify what that illumination method really is.

ALTERNATIVE APPROACH: You can also hook the amps up as simple amplifiers with enough gain to drive the outputs to the rails like below. It requires four more resistors but gets rid of some issues with driving op-amps as comparators.







simulate this circuit