Back side of engine compartment......Mounted to the transmission bellhousing with a single 10MM head bolt. It has a pigtail about 8" long and a 3 wire plug. Remove the air cleaner and aim a flashlight down in there and it will bite you.
If this is a COUPE-2 door.. (MITSUBISHI BUILT) then the crank sensor will be inside the timing cover. You will see a wire running through the cover. It's mounted to the front of the block. NO, you do not have to remove the timing belt...there's room to get it out.