The heater core is in the passenger-side firewall; follow the heater hoses to where they enter the firewall. Use a repair manual for the procedure. If the car must be driven without heat, the two heater lines can be cut and spliced together to bypass the core, but confirm they are standard bulk hose rather than expensive dealer-only lines.
The owner of a 1996 Ford Mustang V6 asked where the failed heater core is located. One reply recommended a repair manual, and another incorrectly compared it to a radiator on a different vehicle. The expert said the core is in the passenger-side firewall, advised following the heater hoses and using a manual, and noted a temporary hose bypass if heat is not needed.
