There is no light that I know of. But to check yours, use a small screwdriver or something smaller and use it to remove the plate P,R,D,1,2,3 are printed on, it's just a long thin black strip with the letters and numbers printed in silver down the middle of it. It's only thin so take care. If you have a light under it there will be a light(duh), but if you don't you will see a couple of gold screws. Simply push the plate back in place.