A couple possibilities are: low coolant level or bad water pump. just based on overheating and no heat, sounds like the thermostat is bad or it could be the water pump thermostat
Overheating. Have the cooling system checked.
how to replace a heater core in a 1997 Chevy blazer
My 2001 Chevy Blazer was blowing cold air when I had the heat on. My husband flushed the line to the heater core and a bunch of junk came out and now my heat works great. My 2001 Chevy Blazer was blowing cold air when I had the heat on. My husband flushed the line to the heater core and a bunch of junk came out and now my heat works great.
try changing thermostst
checkALL of your fuses short could be a problem. i have a 95 blazer, bumps may of screwed up wiring like in mine
Same as a 96 blazer go here.How_do_you_replace_the_blower_motor_on_a_1996_Chevy_blazer
You have to completely remove the dash to get access to the heater core.
Is it blowing cold air only or not blowing any air at all.
If your windows fog up you thermostat may not register because you heater coil may be broken.
pull the handle down
Sounds like a bad head gasket
Maybe a bad switch