Thank you I am back in business. thanks to swartlkk and Dusty. I replaced the rotted hose I found connected to the vacuum outlet from the engine. I now have air coming through the dash vents. Not a day to soon. It is really cold outside. Thanks again
Paul

 

On my '96 Blazer, I found many of the vacuum rubber hoses aged, cracked and splitting due to age. You might also check under the hood to be sure that the vacuum hose going from the engine to the firewall (that feeds the dash vacuum system) is not broken/cracked. My 4WD system stopped working due to a broken vacuum hose; there's hoses all over that over time will age and need replacing.

 

im having the same problem whichever position the switch is in it only goes through the defroster vent and feet vents what exactly is the problem????

 

Did you read the thread? I answered your question in my first reply above.

 

lol ok thanks