03 Z71 Worst HVAC ever?

[PenultimateLap]

Hey all, had my 03 Z71 suburban for about a year now and the auto climate control drives me nuts and am wondering if its all normal. its like it takes the system forever to recognize if its hot or cold and turn on. sometimes it will turn on relatively quick, bit other times it's cold and even though the truck is up to temperature the system takes its time kicking in. and maybe related...rear decided to blow cold when heater is on no matter what the controls are set to, but other times functions normally, but this could be rear blend door? and lastly when i first got it, i thought AC was out, but then it started working a week or two later. now its back to not working or even turning the conpressor on.

So, can these be related to the actual HVAC control? or is some of this how its supposed to work? ive just never had a system thats so slow to respond. i wish it were just manual controls! lol

thanks in advance!

 

[OR VietVet]

You can use just manual controls on that control head, I do on my 2005. The control head may be the problem and are available at ebay. May also have problems with ambient air temp sensor or the cabin air temp sensor.

 

[swathdiver]

Hey all, had my 03 Z71 suburban for about a year now and the auto climate control drives me nuts and am wondering if its all normal. its like it takes the system forever to recognize if its hot or cold and turn on. sometimes it will turn on relatively quick, bit other times it's cold and even though the truck is up to temperature the system takes its time kicking in. and maybe related...rear decided to blow cold when heater is on no matter what the controls are set to, but other times functions normally, but this could be rear blend door? and lastly when i first got it, i thought AC was out, but then it started working a week or two later. now its back to not working or even turning the conpressor on.

So, can these be related to the actual HVAC control? or is some of this how its supposed to work? ive just never had a system thats so slow to respond. i wish it were just manual controls! lol

thanks in advance!

From my chair over here, it seems to me that your system is low on refrigerant first of all. That's why the compressor sometimes works and it doesn't depending on the pressure which is determined by the ambient temperature when it is low. With a 20 year old truck, you may very well have actuators that need replacing as well.

You gotta have a set of gauges, the ubiquitous manifold to see the condition of the system and whether it needs refrigerant or not.

 

[PenultimateLap]

I am curious about swaping to the manual control. i thought it had a different harness? could you elaborate?

I do need to check the refrigerant levels, thats why i havent dug into the ac issue yet until i rule that out.

 

[OR VietVet]

I can use the manual controls on my auto temp control head. I prefer it.

 

[Fless]

The auto HVAC system has multiple temp sensors in the ducts; you'll likely need a Tech 2 to verify they are reporting correctly. You could also check the "calibration" number that is the firmware that is in the HVAC controls (front and rear); there have been updated calibrations for some of these. To update you'd need to be able to program the control.