I'm a newbie here but has been an owner of a 2003 Trailblazer from when it came out but it's my mom and my uncle who are driving the Trailblazer until recently. They live in Palm Desert and it's summer... and when I drove it and turned on the AC, it just kept on blowing hot air. I tried resetting the HVAC fuse and it worked for the first 5-10 minutes then back to hot air. Both vents (driver and passenger sides) are just blowing hot air. I hear the clicking noise coming from the actuator. My question is: which actuator do I need to replace to make sure it's blowing cold air? I know there are several... but my main concern is just replacing the one that controls cold/hot air. Is there also a "short cut" to wherein I could just unplug the cable to that actuator to leave it blowing just cold air?

If you don't mind, please reply with the OEM part number; and if you have an Amazon link of a cheaper alternative, please include that, as well.

TIA

 

Welcome to the Forum!

Well there are multiple HVAC actuators in the 2003 TrailBlazer, with the number of and part numbers for dependent upon whether or not the vehicle has and automatic or standard HVAC system and if it is an EXT model. The automatic system has dials to select a temperature which shows up as a number on the "infotainment center screen" and the driver and passenger sides can have different temperature settings, The standard HVAC system has sliders to set the temperature.

The clicking you hear is indicative of broken gears inside an HVAC actuator.

Now for a few questions:
- Is this an Automatic or a Manual HVAC system?
- After you tried resetting the HVAC system, how cold was the air coming out of the vents?
- How hot is the air coming our of the vents? Hot like Palm Desert temperatures or really, really hot like the heat coming off an automotive radiator?
- Exactly which vents is the air coming out of?
- Is the AC compressor engaging when you select AC on the HVAC controller? This is especially important because it could indicate both a compressor problem and an actuator problem.

Until you answer these questions, I cannot give you accurate part numbers.

Also, you do not want to purchase replacement actuators (especially cheap no-name ones) from Amazon or ebay due to counterfeiting and their being crappy parts. You would be much better served by spending a few dollars more and getting good quality parts from rockauto.com or at a local brick and mortar parts store.

 

I appreciate your response! And to answer your questions:
- It has an automatic HVAC system
- It's blowing really cold air. I'm 100% sure it's the actuator. Actuators really since I could also hear the rear actuator clicking... but my main concern is the front.
- It's blowing hot air like Palm Desert temperature hot. My uncle even mentioned that there are times when he plays around with the control, it would start blowing cold air... but, again, that doesn't last and it goes back to blowing hot air again.
- So, all four vents in the front are working. There's air coming out of all four.
- I haven't really checked the AC compressor... but I figured, if it is able to blow cold air (like a regular car with no AC problems), I assume that the compressor is working and that it doesn't need a refrigerant recharge nor is there a leak.
Hope that helps! And thanks again!

 

OK. Thanks for the added information. Rather than continuing here and confusing things, I'll let you continue the thread on TrailVoy with Ravalli Surfer. He is a retired mechanic with LOTS of experience. One of the Forum Gurus.

See you over there!