I recently installed LED footwell lighting in a 2010 Honda Fit. The LED’s are driven with a PWM dimmer/controller that uses potentiometers to manually adjust the brightness of each of the RGB channels. Any combination of red, green, and blue is possible. The LED’s match the operation of the dome light switch and come on for the same events, e.g. when the door is opened. They also come on when the dome light switch is set to ON. In order to allow the LED’s to fade with the dome light, it was necessary to make a small modification to the dimmer/controller.
During installation I remembered to take lots of photos. I made an instructable with complete details that can be found at the following link: