A/C, heater blower motor stops

[02ws6collectoredition]

  The A/C blower fan will slow down to the point that the car will be hot inside and if I turn it up to high it will blow only slightly more.  I have replaced the blower motor and there was no change.  The fan will act fine for about 30 minutes of driving, but after about an hour there will practically no air coming out of the vents. Has anyone else experienced this condition?

[ob_one1963]

Try these two things. Check that there is nothing blocking the air flow in the duct work. I had a mouse house in mine last year, and they were quite kind to fill the blower up with insulation.
Next, do you get full air in both heat, cool and vent air modes? The car's control is vacuum lines. Open the hood and on the passenger side back by the firewall (just under the hood hinge) is the vacuum controller for your heating, ventilation and air conditioning (HVAC). Make sure all of the hoses are hooked up and not cracked. Also make sure the heater a/c control valve is not broken or smashed either. Paste the following link to your browser for a picture.
http://www.autopartswarehouse.com/products/products.php?make_text=pontiac&year=1993&model_text=firebird&category=climate_control&subcategory=a-fs-c_and_heater_control&part_name=a-fs-c_heater_control

Hope this helps. Rick.

[02ws6collectoredition]

thanks,rick.i will check out your suggestions this weekend.