Got a 2003 H2 with an irritating and frustrating problem...

The car has climate control so it regulates the temperature inside automatic to set temperature.
From 60f + 87f it blows cold from all vents. (I use Celsius on the car so the Fahrenheit is approximately)
When getting to 88f (max) it blows hot from all vents.
There is nothing in-between.
Cold or hot…

I have checked the temperature sensor above the driver and the little fan is working.
The problem is not with any actuator as it changes flawlessly from cold to hot.

So I can choose between freezing or melting.

Of course I can regulate the fan and deactivate the AC manually, but its not an ideal solution.


Any ideas?

Could the temperature sensor be faulty even though the fan is working?
Is there a way to measure resistance to see if it works?
Should this be done at the sensor or behind the control panel? (or maybe both if there is a cable issue)
Is all electronics for the climate control located inside the panel or is there some other control box?


I also have a seat warmer issue where it turns on automatically, I turn it off and it turns back on, I turn it off and it turns back on...... You get the idea...

Found a solution to disconnect the heater elements underneath the seat as a temporary solution.
The car is only used in the summer so we DO NOT want the hemorrhoid grill to be activating by itself…

 

Cannot answer your issue directly, however the attached a PDF describes the HVAC system and it's operation, it may help with your diagnostics.

I seem to recall there have been issues with GM blend-door actuators which may be connected to your issue. This thread discusses similar problems and a recalibration procedure, there may be other procedures either on this forum or on YT (search for HVAC)

A TECH2 may help with troubleshooting.

Keep us posted