Its a 98 model 9200i. I replaced the flap actuator and entire flap assembly under the pax seat. Parts 31, 69, 30 in the diagram.
Little background, recently replaced water pump. Had no heat at all. Its a Detroit. Opened the valve for the water going to the heater under the seat. Heat is working good only up front - driver dash vents and window etc. I tested the the flap assembly before installation. Flap was rotating when turning the sleeper fan speed and it was moving when adjusting temperature knob.
Any help is greatly appreciated.