The case of Curious Head Bulb

So the van's head light went, it is such a simple task.  When I looked at the bulb, it didn't seem burnt, so I took the van to the garage.  I cannot believe the garage said they do not have bulbs in stock!  Luckily, I got the bulb before I went to the garage.  I told him I had a look, but since it didn't look burnt, I thought it maybe fuses.  He said it could just be the gas.  I supposed I should have just tried it!  Silly me!