2005 Touring Blower Motor only works on the "O". Turns off on all other settings.

It is the manual Climate control.  It blows hot or cold if ac or heat is turned on.  It is hard to tell if any of the location settings are working because the fan blows so little.   Ie: defrost, lower, upper, etc.   If you turn the fan speed higher than "O" the blower stops running entirely.  Replaced the blower motor resister as that was cheap and easy to try.  I did notice it got hot.  Changed fuses because also cheap and easy, but I have not gotten to relays yet.  I did check the seating of the fuse looking bits with the diode symbol on them.  I also took two from another 300 and switched them out.  No difference to the functions or lack of them in either car.   The car does have an aftermarket radio, it was that way when we got it.