Air won't blow out of vents

you most likely have a vacuum leak under the hood.check the small vacuum hoses at rear,near the firewall first. start the engine,turn the a/c on high or medium,listen for hissing noise/sounds.if needed,run you hand around the hoses to check for split,dry rotted vacuum hoses.check all the vacuum hoses.when you find the leak,repair it.when you have a vacuum leak,the blower will default to the defrost and/or the floor mode,and will not blow out of the front panel vents.post findings.