so i'm sure we all wonder from time to time, "what bulb goes here?" i found this helpful tool on sylvania's website that will tell you... all you have to do is enter the year, make and model, and it flat out lists all the bulbs for your truck/car i know i am going to find this useful to make a list of all the bulbs i need, to replace them all with LED
OSRAM SYLVANIA - Replacement Guide - Start
also note, that bulb numbers GENERALLY do not need the letter suffix, after the number, the letters are usually a brand specific code, meaning long life bulb or sometimes LED... with the exception of forinstance 1157NA where the NA means amber bulb. Red bulbs will have a similar suffix, but i forget what it is at current. not all bulbs fall into this simple classification though, and the letter could mean something specific of the placement... Also i should mention that if you are currently using an 1156 bulb for a turn signal on the front of your vehicle, and you wanted to go to an amber bulb, because you are putting clear lenses on, it would be a 1156NA, the number is the firment, and it will be identical for the standard bulbs (194/149/219/1156/1157/1175 ect) they will fit others with the same number, but the colour may be different.
I should also include this chart, which may prove useful to some people (even though i don't understand it)