Those old Craftsman/Chamberlain garage door openers had an interesting "feature" (or rather bad light bulb socket design) where the lights would be very sensitive to vibration and would no longer turn on every once in awhile and you would need to tighten the bulbs in the socket <strong>really</strong> hard to prevent them from un-screwing themselves back due to vibration. If you (or a previous owner of the house) did it a couple of times, the central petal of the light bulb socket would be crushed flat and pushed so far back that the contact of a new bulb would no longer reach it hence the circuit would remain open. This would be especially true with some short neck or specialty bulbs.
You could <strong>extremely carefully, *WITH THE POWER CABLE DISCONNECTED*
</strong> grab on the petal with a needle nose pliers and pull it back into its original position or just buy a replacement socket. It is a simple plug-in part, about $6-$10:
Make sure to use only A19 size bulbs, 75W or less , so-called "rough service" like these:
which are designed to work in vibrating environments (the filament is supported better than in a regular bulb)