I have the same symptoms but attributed it to the fresh/recirc door not closing fully. A portion of the pod(short throw) is leaking so the line is capped off. I've tried to match this symptom to what is shown on the schematic but there must be some differences in actual "physical" ductwork than what is shown. With that in mind, have you verified the fresh/recirc door is closing fully?

Also, what are you getting T/V mode?

__________________
Sam

84 300SD 350K+ miles ( Blue Belle )