Electrical Question

My 4x4 and interior lights on my 99 Chevy Blazer are out. I have figured out that the fuse that controls the interior lights are also tied in somehow with the 4x4 electrical connection. It is supposed to be a 10 amp fuse that completley blows as soon as you put a new one in. A 15 amp has the same results. After trying to put in a 25 amp, the interior lights and the 4x4 push button lights will turn on and you can switch from 2 hi/ 4 hi and 4 low. So I know it will engage but the thing is, the 25 amp fuse gets hot and since it calls for a 10 amp fuse, something is wrong. Does anybody know what the problem may be? Other than a short.