1998 Durango. Heater & AC doesn't blow through dash vents. Only blows through window defrost on top of dash. Also, heater & AC is not working. The fan blows good.

 

Sounds like a vacuum leak. Check the hose that goes into the firewall to the dash. Look inside the engine bay. Drivers side on the cab firewall where the throttle body cord comes through and you'll see it. Double check the connection above this before the brake booster off the "T".

 

+2 a vac leak