Ford 2003 Mustang Workshop Manual page 3157

The A/C blower motor (19805 ) pulls air from the air inlet and forces it into the plenum assembly where
it is mixed and distributed.
Heater Hoses
NOTE: The heater water hoses connect to the heater core using quick disconnect couplers. The
couplers are an integral part of the hose assemblies and cannot be separately serviced.
The heater water hoses (18472) provide a flexible connection between the engine and cooling system
allowing hot water to travel from the engine to the heater core.