The radiator should be checked, ice cold and clear full of coolant. I have a 1996 Chevy Blazer 4x4 with a V6-262 4.3L engine. About three weeks ago, the heater stopped blowing heated air. Having a father that teaches automotive technology we decided it must be the thermostat. We replaced thermostat with no success.
Blower works fine.
Coolant level is good. Connecting the scan tool the vehicle temperature only got to 195 after extended running time. Unable to find any info on normal operating temp. For a Blazer we are at a loss. Using the fix of old, we placed cardboard over the radiator and that seems to make it work better not great.