How do you tell which type B fuse has caused Corolla air-con to stop dead with no fan changed 15A fuse under kickboard but suspect it is one under the hood?

On the cover to the engine compartment fuse panel there will be a description of what each one does, if not there is a window in the top of the fuse itself for checking whether it is any good or not. There must be a reason for the fuses to blow, that is what you need to address they just dont pop for no reason and putting in a higher amp fuse wont solve it, in fact it will make things worse by causing the circuits that are being protected by that fuse to possibly melt down and necessitate a much more costly repair.