98 deville: my heat and ac work just fine but why is it only coming from the defroster and floor vent area only? i want it to come out of the dash board vents............i took off the panel under the glove box and i can see the little bar move back and forth if i change the temp. but i just can't figure out why nothing is coming out of the vents???????

 

It's your Mode door that is either stuck or not functioning. The mode door let's the air go to the heat defrost or to the A/C outlets. The problem could be the mode vacuum motor, check the connections coming from the ECC programmer, it will be the tan colored line to the mode motor. Could also be malfunction in programmer. I'd check for stuck mode door first, it's just inside the blower housing near the heater core.