car instruments generally have a color cast…do you need color corrected?
if not then consider adding some of the neon/led lighting that plug into your cigarette lighter socket.
add them to places (like the instrument panel) where people expect light to come from. (gives you more light overall, but still looks fairly normal).
then use small clip on type lamps inside the car, (ac inverter and 40 watt daylight balanced accent lights from hardware store)and larger lights from outside the car to light your subject.
also see "day for night" tutorials.
