Simple, by using colored LED (or incandescent) bulbs. After all, put a red bulb behind even the most faded lens and it is still red. I used 24 LED 1157 style bulb for the brake/parking light plus a small wedge bulb for the side parking light. Also above is a 30 LED narrow beam white backup light bulb. LED lamps from http://www.superbrightleds.com. I left the turn signal bulb stock due to some issues with the flasher relay.   (6/7)