Drove my "new" used 1990 Buick Reatta from Dover DE to Denver CO the past 3 days. The dealer replaced the blower motor just before I began the drive cross country. When using the ACC system manually to switch modes for air delivery between different outlets (Heat, Bi-Level, Defrost, Dash) the system did not redirect the air. Somehow either the heater box door is not getting the signal to change position(s) or it's blocked. Any ideas which it may most likely be and how to diagnose it without tearing the entire system apart? Thanks for any help! Mike

the car is old enough that it might use vacuum to activate the blend doors. check for hoses loose. if it has an electric blend door actuator, that could be bad.

Thanks Mike. I took a look today at the firewall and it would appear that the door(s) are electrically actuated, but I don't have the time yet to dig into it from the interior side - behind the jockey box I am assuming if it's a typical GM config. These are the same as the Riv's and the Allante's so I was hoping someone could tell me if it was vacumn or electrical actuation since I don't have the service manual on hand yet (it's on order). I'd like to get some heat out of this darn thing in the meantime! It heats just fine, I just can't direct it anywhere! Thanks, Mike Wood