2004 XLT with manual ac/heat controls. 1, 2, and 3 stopped working on the fan speed dial so I went to Ford and bought a blower motor resistor. Problem solved, heat would blow on all speeds. Now it's been a month and it doesn't blow at all, but you can feel the heat radiating out of the vents. Also I did take the dash apart for a sound system install and I carefully removed the connectors from the back of the 3 heat/ac dials, reinstalled correctly though but thats's about the time it stopped working. Is there a fuse or anything else I should check? Thanks