I have a 94 z-28 with automatic, totally stock and i have heater issues the fan blows cold and the heater core gets hot but it will not blow hot air. I pulled the blower motor out and discovered that the little vent thing under the windshield pumps directly to the blower motor is that right? Maybe there is a sensor or relay that controls something i cant see? I am all out of ideas and summer time aint coming fast enough any help would be greatly appreciated

 

hmmm. Heater system only have a few parts. If the core gets hot and there is air blowing throw it then you should have hot air blowing into the cab. When was the last time the heater worked. And are you sure the core is getting hot and the blower is moving the correct amount of air down to it.

 

I would be wiling to bet that your heater core is clogged (and thus not getting hot), it seems to be a common issue.

 

thanks for the advice unfortunatly it didn't work.

 

If the core is really getting hot and the heater fan working, then the air is not being circulated through the heater core. Check that the fins of the heater core are not covered with dirt. Check the temp control cable that moves the temp air doors in the HVAC plenum, and also check that the rest of the air doors are working and that there are no vacuum leaks in the air door control system.