Hi,

Have a 2001 Trailblazer, that no matter what i try the heater and fan stay on, even when i turn the selector to cold?, ive had to disconnect the AC pump (its rooted and cant seem to find a replacement pump here in australia, there are no serial numbers for it on the pump itself).

Problem ive had, the heater fan USED to switch down to cold air up until a few months ago, but ever since it seems to blow hot air regardless, ive disconnected the HVAC fuse to kill the electricals to the fan to stop it blowing hot air (its summer over here at the moment, and with temps at 42degrees Celsius you dont need hot air).

Is there something i should be looking at to get the fan to at least blow cold air when i select cold air, rather than constant hot air ?

Any help would be greatly appreciated.

 

sounds like the resistor is bad and set to default, which is high.

 

Tell us a bit more about your truck? Auto or manual client control? Can you change the fan speed or is it constant? If it blows hot air all the time instead of outside (cooler) air when you select it the problem is with the actuator or controller not the fan itself.

 

She's a 2001 TrailBlazer LT (auto)

its just blowing constant hot air event though the selector is set to cold air.

 

My first guess is you're having a problem with the temperature actuator. There's a plastic gear on it that get brittle and breaks apart and you lose temperature control. There's also a possibility it simply got confused. Remove the RADIO BATT fuse from the instrument panel fuse block for 30 seconds (check it while it's out). Put the fuse back in and turn the key on, wait 10 seconds before starting it. The actuator will cycle back and forth to find its limits and calibrate itself. Personally I can't hear the thing but it's on top of your heater box behind the glove box. Free to try anyhow. The other fuse you can check is HVAC1 in the IP fuseblock. The other possibilities are a bad control module or a bad temperature sensor and with the auto system the ability to read codes would be nice (compared to throwing random parts at it).

 

Sorted out the problem...

The problem with the cold air, is the same as every make of car out there.

If the AC Pump is disconnected or not working, even though the heater box has a fan, it will just suck hot air and pump that through the system, you need the AC pump going without the AC on, to produce cold air.

Just have to find a new compressor for mine now, theres no part number on the AC pump and she definately needs a regas.

Thanks for the help guys...