As Bob says, the position light is a tail light. Not always easy to tell which one, but when you find it take the bulb in to the store for a match. The number listed in the owners' manual does not always make a lot of sense. I found that my position light had some weird number that the NAPA store couldn't cross. I pulled the bulb and found that the bulb is a perfectly standard 1157. Getting them out can be pretty easy, getting them in can be uncomfortable.