Thermostat stuck closed, low of coolant, water pump failure, cooling fan failure, or blown head gasket.
heat not working
catalytic converter
Thermostat, or fan motor if it does not blow hard.
Check coolant level check blower motor fuse Check the thermostat
Clutch slippage can cause an engine to overheat by running the engine at higher rpm's than what it is recommended for the motor. Excessive heat in the engine can cause the head gaskets to leak building up heat in the motor. There are inexpensive kits to test whether your headgasket is leaking or not.
Blend door actuator.
just checking why heat in front don't work and heat in back dose 2003 Mazda mpv
Your heater coil is bad.
Thermostat stuck open. Replace! A low coolant level will also cause this problem. The blend door could be stuck also.
Copper is the best base metal for conducting electricity. Gold and silver are better but too expensive. If you used a poorer metal you would lose more power and it would also generate more heat which in a motor would be quite a lot. More heat would then cause more resistance which would cause more heat.
The most common problem causing a 2000 Blazer to stay on heat is a problem with the blend door. Check the blend door and its control circuit to fix the problem.
You can calculate the quantity of energy that a motor turns into heat with either one of these equations: Heat energy = ( 1 - efficiency of the motor) x (energy input to the motor) or Heat energy = ( 1 - efficiency of the motor) x (power input to the motor) x (running time)