Carrier indoor air handler keeps immediately blowing 5 amp fuse. Changed contactor on the outside unit and turned on the breaker and air handler fan came on. Went to thermostat selected a/c and compressor came on turned it to off and compessor stopped but air handler fan won't. Made sure fan was in auto. But nothing I try will turn off the fan. After probably about 15 minutes of running it blew the fuse again. Tried a new fuse and it blew it immediately like before I changed the contactor. Seems like I may have fried the new contactor. Seems like there is another problem that is making the air handler fan run constantly until it cooks the contactor.

Start be checking for a short in low voltage wiring, check both the wires from tstat to the airhandler ,also the tstat wire that run from the airhandler to the outside condenser unit