Glad I found this thread (and since joined the group). My driver's side front turn indicator died on me, so of course I look up the bulb, go buy one, remove the plastic to get at it - only to find that it's not the same bulb. Totally different base. The "book" says it's a amber 4157, but it's really a 1156 / 7507 type bulb. So now I have to go back in there again to replace it.
Lesson learned, "the book" isn't always correct. Well, at least I found this forum.