You will likely need to:
* Remove the glove box. This provides better access to the area.
* Remove various trim pieces around the HVAC system.
* Possibly remove the HVAC housing itself to get to the module.
Because of the complexity involved, it's recommended to consult a repair manual specific to your 2001 Lincoln Town Car before attempting this repair. A wiring diagram will be extremely helpful in identifying the module. Improper disassembly could damage other components.