How do you change the heater core on your 97 Cadillac Deville?

  1. Disconnect the negative battery cable.

  2. Drain and recycle the engine coolant.
  3. Disconnect the heater core hoses using tool J-37097 or equivalent.

  4. Remove the right side sound insulator and the glove box module.
  5. Remove the programmer shield, if equipped, and disconnect the air mix valve link.
  6. Disconnect the programmer vacuum and electrical connectors.
  7. Remove the heater core cover, leaving the programmer attached.
  8. Remove the heater core retaining screws and the heater core.