The left rear tail light "red" bulb on my 1999 S2000 only works when the brakes are pressed... does not work when I switch on the night time lights. The right side works in both cases, at night and under braking. So something's wrong with the left.

I looked in the tail light assembly and saw that there's only one "red" bulb in there (and two other bulbs are the "yellow" turn signals and "white" reverse). Since that one "red" bulb works under braking, I'm assuming it's not just a blown light bulb? Unless it's some sort of two-in-one bulb

 

its a two in one bulb

 

thanks man