Hi everyone, just bought a 1998 blazer 2 days ago. First thing I noticed, no heat. After reading forums i found the heater core was clogged. got that all flushed out....(easy). The I open the gate from HELL!!!! now I ca't get the heater to blow cool. Everything works as far as blower control. But I have eyeball drying heat coming out the vents even with the heater off. I tried reading up on heater the heater bu the manual says the AUTO CLIMATE can only be serviced by dealership....Can someone advise on closing the door from HELL... I live in California and its not exactly cold these days. PLEASE HELP!!!!

 

The heater core is at all times the same temperture as the coolant.

There is a door that controls where the heat from it reaches the cabin or NOT.

Since you may be going into the dash to replace the heater core (our 2002 required it a few years ago thanks in part to Dexcool usage) in the future you might consider a manual shut off valve on the inlet side but that could create a bleeding problem due to no path for coolant flow in that part of the cooling system.

You need to see if that door is physically broken or just has a control problem. Switching to AC mode should cause that door to close completely so see if all heat flow stops as soon as the AC is turned on. Let us know what you find.

 

Welcome from New York. As for your heat concern check the 2nd gen tech section on the forum. Good luck.