I have an issue with one of the chase lamps not working on the helmet of my BOP.
I've ruled out the bulb and bulb socket as being the issue. The board looks nice and clean and the traces appear perfect. The bulb works when hack/hotwired to the next bulb over.

I think that what's going on is that each bulb has a diode associated with it, and the board uses a common ground for all the bulbs. I think that the diode with this particular bulb is bad.
Does this seem right?
Is that really a diode? I have no idea how to tell a diode from a resistor from my elbow.
Can I just replace it? and what size/spec should it be?

Thanks.

The lamp sockets are the type that can be screwed out of the board. Swapped with a working one, and the same location is still out while the original socket works in the other location.

Thanks Floyd. I think you're right that I'm right.
Did some additional research and the moral of the story is "CHECK THE MANUAL".
Manual shows that is a 1N4004 1.0A diode. (Hah! My guess was right!)
Looks to be available at Radio Shack for less than two bucks.

Will likely try to replace it this weekend.

Edit: Here's an online review of the diode posted on the Raido Shack site. Looks like I REALLY need this diode:

Comments about RadioShack 1N4004 Micro 1-Amp Rectifier Diode:
OMG! These are the best diodes on the planet Earth. I absolutely screamed with excitement as I roughly thrust them into my PCB, and soldered them with abandon into my circuits. These are much better than the ones I was getting from House of Diodes, the Diode House, or Diode-a-rama. They also taste great with guacamole.