[chargerjake]

I've driven my 2017 Camaro 2LT V6 for about 60,500 miles now, and just recently replaced the thermostat and engine coolant temperature sensor.

It first encountered the thermostat issue at around 40,000 miles (where sensor stops reading and thermostat fails into open position running fan full speed). It did that once or twice and I figured it was a fluke deal because it never did it again until 60,100 miles (quite convenient). It proceeded to repeat at least 5 times, so I ordered new parts and replaced them myself.

Whilst all this was happening, I started noticing around 50,000 or so miles that my driver side dual zone climate control vents only blow hot or cold air, while the passenger side blows correct temp. For example, on a cold day, I would crank the heat to warm up the interior, then drop it down to 72 or so, that way I don't cook myself. However, the car continues to blow 90 degree air, only on the driver side. The passenger side works fine and feels like it's blowing out the correct temperature air. If I continue to slowly turn the vent cooler, it won't respond until about 65 deg or so, at which point it slowly lowers temperatures until it reaches the lowest temperature. It's almost as if it only blows air at the two extremes.

Regarding the thermostat issue, I heard that climate control/heating issues could also happen when a thermostat or sensor fails, so I was partly expecting that this problem would fix itself after I fixed the thermostat, but to no avail. Going into a cold winter in Oklahoma, I'd like to see if I could find the cause of this issue so I can get my climate control working again.

I've done some preliminary research and there are some mentions of just recharging the A/C. Others say that there are temperature sensor(s) in the interior of the car (where, though?) and I've seen mention that it could be the blend door actuator on the driver side.

Has anyone encountered this issue before and/or knows what it could possibly be?

[ctrlz]

Maybe you will get lucky and can pick up a DTC with a code scanner. This is just a small bit of what is in the repair manual. The manual is kind of geared toward having a dealer scan tool which lets you check performance of the various actuators and sensors.

DIAGNOSTIC INFORMATION AND PROCEDURES > DTC B0223, B0228, B0233, B0408,
B0413, B0418, B0423, B1395, OR B374A: RECIRCULATION CONTROL,
RECIRCULATION POSITION, AIR FLOW CONTROL, TEMPERATURE CONTROL,
TEMPERATURE POSITION, CONTROL MODULE VOLTAGE, AIR FLOW CONTROL
POSITION > CIRCUIT/SYSTEM DESCRIPTION

Doors in the HVAC case assembly are used to control air flow. The HVAC control module operates the
doors through the use of actuators, with one actuator being used for each door. The system has the
following air control doors and associated actuators: mode, left and right temperature, and recirculation.
Each actuator used in the system is a 5-wire bi-directional electric motor that incorporate a feedback
potentiometer. The five circuits are, low reference, 5 V reference, actuator position signal, and two
control circuits. The control circuits use either a ground or 12 V value to coordinate the actuator
movement. In order to move the actuator, the HVAC control module grounds one of the control circuits
while providing the other with 12 V. The HVAC control module reverses the polarity of the control circuits
to move the actuator in the opposite direction.
When the actuator shaft rotates, the potentiometer's sliding contact changes the door position signal
between 0-5 V. The HVAC control module converts the voltage signal to counts. The total range of the
counts is 0-1024, with an operating range between 20-1000. The actual operating range of an actuator
is determined during calibration. During calibration, the actuator is moved though its full range of travel
and the module stores the minimum and maximum value. Based on the desired system operation, the
module sets a commanded, or targeted, value for the actuators. The control circuits are operated to
move the door to the required position, and the changing position signal is sent to the module. Once the
actual position signal and the commanded value are the same, the module ceases operating the control

circuits and the actuator (and door) remain in the desired position.

I also uploaded this schematic which shows the number of sensors and actuators involved:

[SSgtSS1LE]

The duct temperature sensors (22801046) are installed in the air distribution ducts and measure the temperature of the air that streams from the ducts. The HVAC control module uses these values to adjust the mixed air door position according to the requested temperature.

RPO CJ2 dual climate systems have two of them located behind the Radio Control Assembly and the other two are located under the dash up stream of the floor outlets.

RPO C68 single climate systems have one of them located behind the Radio Control Assembly and the other one is located under the dash on the left side up stream of the driver side floor outlet.

You will need a quality ODB2 scan tool and not a code reader to determine which sensor is not reading the correct temperature prior to replacement. They are a pain to remove if you do not have a forked pry tool and be careful not to drop the upper sensor inside the dash.

[ctrlz]

Nice detailed info, SSgt!
Looks like those sensors have a Christmas tree type base.
I would invest in the pry tool (or a cheap set from Harbor Freight) to dig these out. Might want to put some masking take on the back end before you pry to give it a tail in case it goes flying.

[chargerjake]

Originally Posted by SSgtSS1LE

The duct temperature sensors (22801046) are installed in the air distribution ducts and measure the temperature of the air that streams from the ducts. The HVAC control module uses these values to adjust the mixed air door position according to the requested temperature.

RPO CJ2 dual climate systems have two of them located behind the Radio Control Assembly and the other two are located under the dash up stream of the floor outlets.

RPO C68 single climate systems have one of them located behind the Radio Control Assembly and the other one is located under the dash on the left side up stream of the driver side floor outlet.

You will need a quality ODB2 scan tool and not a code reader to determine which sensor is not reading the correct temperature prior to replacement. They are a pain to remove if you do not have a forked pry tool and be careful not to drop the upper sensor inside the dash.

That info is incredible! Thank you for providing that. I'm going to investigate those sensors. Do you have any specific recommendation for an OBD2 scan tool? I have a cheap one from Walmart but I'm going to assume that would be classified as a code reader and not a scanner, considering I can't find any interior temperature sensors on it.

[SSgtSS1LE]

If you know your way around a personal computer, then you might try VXDiag VCX NANO Diagnostic Tool for GM. It uses GM Global Diagnostic System 2 (GDS2) software with their version of a GM Multiple Diagnostic Interface (MDI) Tool to make the GM GDS2 software work.

Warning: it comes from Mainland China and will cause problems with virus protection (add exclusion for each file it finds), so use on a laptop dedicated as a scan tool only. Also, search YouTube for multiple videos on the VCX Nano GM.



Camaro with C68 Single Climate System, HVAC Control Module Example Data:

Note 1: Vehicles with C68 installed will show very high and low temperatures for right duct air temperature sensors.

Note 2: A failed duct air temperature sensor will show very high or low temperatures.



Another scan tool that could be used and not as powerful as the GM GDS2 is AutoEnginuity Giotto Version (acquired by Drew Technologies January 2020) with Enhanced GM-family Expansion.