Originally Posted by Predarat
Totally depends on the model, some you just open a drawer, take it out with a few screws, either clean or replace it and put it it back. Some models you pretty much have to take the damn thing apart and put it back together. As others have mentioned you may be able to clean and spray it with a can of air to fix it.
Pretty much this. If the fan is right under a removable plate, it'll be easy. But a lot of those are buried deep in there and are a major PITA to get to. You'll pretty much need to either find a repair manual or just start taking pieces off to get a feel for how much work it's going to be.