Another HVAC issue post...

[AllenBrowning]

The Tech-2 eliminates any guess work into what is going wrong. There are two temperature actuators, one for the driver and passenger. The driver's side actuator is under the passenger footwell, just to the right of the center console and left of the cabin filters. The passenger side is directly above, more or less, accessed through the glove box usually. The guts are the same but we have different generations so consider that. You correctly identified the other two, Mode and Recirculate.

Even after researching these actuators for three years, I still came across conflicting information. Several GM dealership websites and ACDelco all gave conflicting information. The first actuator purchased was the wrong one of course. Ordered the other and all was well. When the wrong one was in, AC was blowing hot, counts were backwards almost like we put it in backwards which is physically impossible.

On the GMT900s, if you replace the main control unit, it has to be programmed. Not plug and play.

Thxs for responding! How do I access the driver’s temp actuator? That’s the one I can’t locate. I’ve disassemble the entire dash, cut the air duct, removed glove box and air bog, radio, hvac controls. Only thing I see is a cover on top of the hvac system covering cabin filters. But no actuator...

 

[swathdiver]

Thxs for responding! How do I access the driver’s temp actuator? That’s the one I can’t locate. I’ve disassemble the entire dash, cut the air duct, removed glove box and air bog, radio, hvac controls. Only thing I see is a cover on top of the hvac system covering cabin filters. But no actuator...

It is underneath the dash in the passenger foot well between the center console and cabin filter.

After responding to this I came across an article that might explain your problem: https://sparkys-answers.com/2017/01...o-poor-heat-if-temperature-set-below-90f.html

 

[AllenBrowning]

interesting, I’ll have to check into that. I as well had thought it was something to do with OnStar.

in the diagram, that actuator I thought was the temperature blend actuator? That one functions properly. I can hear the door open and close when going thru the calibration. I have replaced that one along with the mode door located above the accelerator pedal, and the recirc located under the duct work against the firewall. Where is the forth? I’m extremely frustrated with this vehicle. It only has 36k miles all highway miles and the hvac has never worked properly since I purchased it last summer. I’m very mechanically inclined and have a lot of experience working on cars which is why I’m so frustrated that I can’t figure this out. Thx again for helping![/QUOTE]

 

[swathdiver]

interesting, I’ll have to check into that. I as well had thought it was something to do with OnStar.

in the diagram, that actuator I thought was the temperature blend actuator? That one functions properly. I can hear the door open and close when going thru the calibration. I have replaced that one along with the mode door located above the accelerator pedal, and the recirc located under the duct work against the firewall. Where is the forth? I’m extremely frustrated with this vehicle. It only has 36k miles all highway miles and the hvac has never worked properly since I purchased it last summer. I’m very mechanically inclined and have a lot of experience working on cars which is why I’m so frustrated that I can’t figure this out. Thx again for helping!

[/QUOTE]

Allen, you can't work on these modern cars without a bi-directional scan tool. If I hooked my Tech-2 up to your truck, I'd know what was wrong in 30 seconds and you wouldn't be tearing your hair out ripping the dash apart replacing good parts.

Actuators can fail in 3 ways and each trouble code provides a symptom or reason for the failure. Quite often, they get stuck. So you may hear them move but that does not mean a gear inside does not have broken teeth or the grease has hardened causing the assembly to freeze.

There's another device that can work on a tablet or laptop running Tech2Win called a VXDIAG NANO. These are wired or bluetooth devices that connect to the aforementioned computers and the truck's OBDII port and work like a Tech-2 for about 1/3 the cost (if you have laptop or tablet).

The Tech-2 or its equivalent is the most important tool in your toolbox and its missing.

 

[AllenBrowning]

I have a standard diagnostics scan tool. I’m guessing the Tech-2 is a bit different?

 

[Tonyrodz]

I have a standard diagnostics scan tool. I’m guessing the Tech-2 is a bit different?

Yes, way different.

 

[S33k3r]

There's another device that can work on a tablet or laptop running Tech2Win called a VXDIAG NANO. These are wired or bluetooth devices that connect to the aforementioned computers and the truck's OBDII port and work like a Tech-2 for about 1/3 the cost (if you have laptop or tablet). [/QUOTE]

Any idea on where to buy one of these? Amazon has them for $109, but says to disable AV software when loading their software. Red flag for me. I went to their site, but they suggest ordering from the US. When I go to the suggested link, there is no listing for GM...

Thanks!

 

[Tonyrodz]

There's another device that can work on a tablet or laptop running Tech2Win called a VXDIAG NANO. These are wired or bluetooth devices that connect to the aforementioned computers and the truck's OBDII port and work like a Tech-2 for about 1/3 the cost (if you have laptop or tablet).

Any idea on where to buy one of these? Amazon has them for $109, but says to disable AV software when loading their software. Red flag for me. I went to their site, but they suggest ordering from the US. When I go to the suggested link, there is no listing for GM...

Thanks![/QUOTE]
I'm sure @swathdiver or @Doubeleive would know.

 

[96-2D-Hoe]

Any idea on where to buy one of these?

No go with your Tech 2 then?

 

[Tonyrodz]

No go with your Tech 2 then?

I don't know why it quoted like that. I was just answering @S33k3r's question.