I noticed my fog lamp was not turning on, after closer examination I noticed there was something going on inside, seems like corrosion?? Should I replace the whole lamp or just bulb?
I would replace the back portion, if posible, and clean and keep the glass.
Replacing just the bulb wont do much, as water will get into it, and most likely kill the bulb again.
I had a cracked fog light that had more "stuff" in it than the on in your picture. It worked fine for a long time. I replaced it simply because it looked ghetto, but again, it worked fine. It might be a bad bulb or a bad connection as Veik said. Simply undo the undercover behind the fog lights to access the plugs and the bulb. Or you can remove the fog light and and disassemble it to clean out the debris.
Here's a good How-To on taking off the fog light ---> CLICKY
If you don't want to waste any money on a new fog lamp, use clear silicon to seal it up and when you put in a new bulb, apply some dielectric grease in the socket to keep moisture out. Hope this helps
my driver's side looks just like that honestly. When I put the yellow bulbs in I noticed there was shards of glass on the inside...and a hole in the lens. Grrr..... I dabbed a lil clear silicon over the hole from the inside and ran a thin bead around the gasket when I reassembled. Still working.