Swap between two colors without an additional light?
8 relays, plus 8 diodes for full features.







simulate this circuit &ndash; Schematic created using CircuitLab

You can probably reduce the number of low end relays, if you run 6 ground wires back to a single relay (Brake Blue, Front Green, Both Turn's Blue and Green). And if you don't want the brake or headlight leds to turn on with the existing brake or headlights, you could remove those as well.







simulate this circuit

Frankly, I think it may be cheaper and simpler to have two sets of led strips, with a single switch controlling which one gets power. Less wires to run, less relays to buy and wire up.