You need 3 things for a light to work. Intact bulb, power, ground. Which one is missing? Also keep in mind if there is corrosion in a wire, you can read correct voltage with a meter but the resistance in the wire will consume all the voltage when the bulb's in place.
Remove the light so the pigtail and bulb are hanging free. Take a long chunk of wire, hook it to battery ground. Put a paper clip on the other end and poke it into the ground side of the socket with the light switch turned on. Of course if you poke it into the power side, bye bye fuse. See if this gets the light to turn on. If not, do the same thing on the positive side of the battery. I recommend putting a fuse in your 'test' wire at this point, because if you bump it to anything grounded the wire will go up in smoke.
All you're really doing is one at a time, providing what the circuit needs to operate, when you get the light to come on you know if the issue is power or ground.
It's usually ground, by the way.