01 front foglight problem

Does anyone know what components could cause my driver side foglight not to light up? I thought it was the bulb, so I changed it being careful not to touch the bulb itself. It still didn't light, so I removed the bulb and tested it with a battery charger and the bulb is fine. Then I tested the original bulb that I had thought was burned out, and it was fine too. I don't see any loose wires and the socket looks ok. I checked the fuses as listed in the owners manual and they were fine. I see there is a relay but it is for both foglights and the other one is working. Any ideas out there?

Rusty teminals in the socket?

After taking the socket out, testing it, and resoldering the wires, it still wouldn't light. As a last resort I wiggled and tapped all the fuses and relays in the fuse box under the hood. Guess what? Now it works fine.