'98 Concorde Blower Fan Stuck on High

I've read all the other posts about the problem with the Concorde ATC so I replaced the ATC head in the dash with another I bought off E-Bay. I still have the same problem, with the blower fan running on high but everything else seems to work OK. When I put the unit in manual mode the blower still stays on high and the knob has no effect. The only way to stop the blower is to pull the fuse. Do I have another bad ATC or is there something else I should check? Otherwise, I can't complain. 186,000 miles on my 3.2L and nothing worse than a burned out taillight for the first 150k miles. I've still never had to add oil between my every 10k oil changes.