The lighthouse bulb is an item in the Fallout 3 add-on Point Lookout.
A very large bulb, it can be used to fix the signal on top of Point Lookouts lighthouse.
- Only one can be found in the truck wreckage, the rest are shattered beyond repair.
Sometimes the lighthouse bulb will not be in in the truck. Instead of, the lighthouse bulb and maybe some other objects normally being in the truck can be found stuck in the air, relatively near the truck wreckage.
Sometimes, you'll see the floating objects (as mentioned above), but the lighthouse bulb will appear on the ground on the outside of the truck on the northwestern edge of the trailer (if you are looking from behind the trailer). It's under the trailer, but visible.