more than likely your heater core is clogged. GM's extended life anti-freeze can become very gummy after 2years. The simplest thing to do is to back flush the heater core. There are two heater hoses going to it [located on the passager side fire wall]. Remove the clamps and hoses from the heater core and simply stick a running garden hose one of the nipples. If water doesn't come out of the other nipple in a few seconds, move the hose to the other nipple. Chances are that you will get a nasty glob of slime coming out. Repeat the process several times until you only get clean water coming out in both directions. The heater core is now clean and you may reconnect the two hoses. Start car and allow some temperature to build up. You should find a nice warm heat coming from the heater now.
heater hoses might have been disconected
Check coolant level .Then thermostat . Then hearter core
They did'NT make the Trailblazer in 2000 might you be looking for information for a 2000 Blazer.
Yes, have had a problem with the heat since last winter. They finally diagmosed that it might be the heater core. Back heat is working perfect, front heat blows luke warm air. There's $850 that I didn't need to spend.
Engine coolant sensor may be bad
low coolant level, malfunctioning thermostat, clogged heater core, malfunctioning heater control valve, malfunctioning climate control programmer,
check your freon level. you might need to fill it back up. also your thermostat might be going out. does it ever over heat?
check your thermostat, if that isn't it you might need a new heater core. had one put in my f150 for about $150. With my car, it was Heater matrix clogged with radiator sealant. The workshop cleaned it and it's start working fine!
The 2001 Chevy Blazer does have an ignition security system that is controlled by the computer in the vehicle. The light might come on because of an error that is coming up in the computer due to a key problem or an ignition problem. This is a common issue with the 2000 and 2001 Blazer.
The heater might blow cold air in a 2000 Silverado because the thermostat is sticking and not changing from cold to heat. The thermostat is usually located in a hose that leads from the radiator to the motor.
could be head gasket problem. does your heater work? might need heater core , clogged up. do compression test. or bypass heater core and see if that works.
you might want to check and see if the heater core is bypassed