Mark K

You won't ever get heat from the ceiling vents. Those are AC vents only. The rear heat comes from a vent on the right side of the 3'd row; turn on the rear heat and turn the fan up to 6; then follow the noise. Heat for the 2d row comes from vents under the front driver and passenger seats. The rear heater core is mounted behind the trim panel in the rear of the vehicle on the right side. The heater hoses and pipes run from the engine compartment under the car to the rear heater core.