trying to replace blend door motor (top side) on 98 towncar. ATC. Before reassembling I plugged the new motor into the harness and fired up the vehicle and AC. Previously it blew only heat. Self test indicated 24.Motor started turning and never stopped as if it was looking for home positition. Self test still indicates 24. Old motor does the same thing. Do I have a control module problem? From the looks of the motor its only supposed to rotate 90 degrees and has a built in position indicator, rheostat wiper. This really is one tough job working through the glove box door. thanks.