Two problems related to defogger heater have been reported for the 2001 Chevrolet Blazer. The most recently reported issues are listed below.
Vehicle was parked when all of a sudden it caught on fire due to an electrical short in the heater.
I own a 2001 chevy Blazer. Lost heat in Jan. 2004. Took it to dealer. They flushed the system and replaced thermostat. 3 to 4 weeks later the same thing . They cleaned out filter. 30 days later it happened again. They said the filter was clogged again. As the weather warmed up I didn't need the heat. As the colder weather approached again, used the heat 2 times and the 3 rd time the heater core went out completely. When I returned to the dealer there were about 10 other Blazers there for the same reason. They say it is our problem now. Now without heat and have to keep air conditioner on and still smell coolant inside the vehicle. If there is that many vehicles with the same problem then , I would say it was defective parts used. To replace the part is almost $200. And with labor over $600. To have to put out that kind of money on vehicle that is only 3 years old is wrong for consumers. To leave it unattended could be a health hazard, with coolant entering the inside of the vehicle.