I own a 1999 Blazer with a 4.3L vortec engine. I had this problem and solved it by topping up the coolant level. I found if the coolant level got even a little bit low the heater would only blow out lukewarm or cold air. I know this sounds simple but it worked for me. DL Vancouver Island British Coulmbia
Short in the circuit somewhere. Try unplugging the blower motor, closing the circuit with a test lead or test light, and seeing if it blows then. If not, the problem would seem to be in the blower motor itself.
my chevy blazer 1984 the air conditioner blows from down side only.
You have a bad blower motor resister.........
A glass blower is a person that blows glass.
Faulty Function selector switch. Consider replacement.
blower motor resistor
It has a bad "Blower Motor Resistor" The fan switch itself is fine.
it's a problem with the blower motor resistor
there are resistors located by blower motor. could be open. they control blower speed.
Replace the blower motor also.
It will be located somewhere in the path of the air that the blower motor blows.
I have a 1999 blazer. The heater core clogs up about once a year from the Dexcool. Try having it (heater core) flushed and use Prestone (Extended life) instead of Texaco.
You have a vacuum line disconnected or broken under the hood, check in the area around the master cylinder and the vacuum reservoir.
As for why it blows only on the high speed you most likely will have a bad blower resister and for the noise, it could be a bad blower motor, bad blower wheel or trash that is stuck in the blower wheel or housing.......
thermostat is stuck open.
My s-10 does the same thing. I have found out that it only blows when I place the blower motor in speed 4. If I unplug the blower motor and put the switch to 4 it does not blow. I have recently replaced the blower motor and resistor and this had no effect. Hope this helps.
Somewhere in the path of the air that the rear blower motor blows
It could be the actuator that diverts the air through the heater core. Our enthusiasts forum may be able to help you more at www.trailvoy.com
White smoke is from burning radiator fluent.
Inside dashboard in path of air that blower motor blows.
The blower is blowing alittle air threw but not alot. Like it should be doing. It blows heat good threw the other ducts but not deforst duct. What could be the problem. I will be glad if anyone can help me out . thz
The blower head is wearing out. Same thing happened to my Chevy. Cost $284 for new part.
probably the heater core is plugged
I think you should look at your fuse panels and see if you have a blown fuse . Some vehicles have a fuse for high and low blower speeds. Your problem is either the blower motor switch itself or a defective Blower Motor Resistor Pack. More than likely the Resistor Pack is defective.
Be sure it is not low on coolant. It may also be a bad thermostat.