tail light problems

Just wondering about my tail light only lighting up when braking. Is the rear light only a brake light or should it light up at night with the lights on. This may sound like a dumb question but don't understand.

Your tail light should certainly light up without the brake on. It is a tail/brake light.

Those bulbs have two filaments. Have you checked to see if one is burned out? One filament will work even if the other doesn't.

If that isn't the case, you may have to test your wires to see if you are getting power.

This post should be in electrical as compared to engine, but I am sure nobody will be too upset!!

There is a 8W filament for the tail light and an 18W filament for brake. The tail light could be burned out and brake still work.