Heater Temp Control 2002 PA

I wonder if anyone might know the answer to this. When adjusting the temp control to cooler, the adjustment goes down in 1 degree increments until 65 degrees. It then skips 5 degrees to 60 degrees. In my vehicle, 65 degrees is too warm. When I go down one more button push, it goes to 60 degrees, which is too cool. As a result, I am often toggling the button between 60 and 65 degrees, or I roll the windows down to cool off. I sometimes just shut it off, but you lose defrost, etc.

Is there a way to somehow calibrate this? The actual temperature in the car is warmer than what it says when set at 65 degrees.

This is an auto temp system....is it also a dual system?

When lowering the temp, it goes down one degree at a time, until it reaches 65.....then it goes to 60, which is FULL COLD override.....the same happens at the other end.....temp rises one degree at a time until 85......then it goes to 90, which is full heat override.....

At 60, there is no adjustment....you are in full cold mode.....the A/C compressor is running, and there is no temperature adjustment, the temp doors stay in full cold mode......the same happens at 90.....the A/C compressor is turned off, and the temp doors go to full heat and stay there.....

Any setting between 65 and 85, the control head will be constantly changing blower speed and also output temp, depending on what setting you have the control head set at AND what the temp sensors are reading.......

For example, let's say you have it set at 75......If you get in a cold car, and start it, the inside temp sensor will command heat to come out of the registers(there will be a delay, because it also senses that the coolant temp is not warm yet....when the coolant temp rises in the heater core, the blower will come on high, and blow warm air)....as temp of the car approaches the 75 logarithm, the blower speed will slow down, and the actual temp will change from hot to warm.....

For another example, let's say it is set at 75, and the car has been sitting in a hot sun all day....in this case, the inside of the car is hot....as soon as you start the car, the inside tempo sensor senses the heat, and the control head will start the blower on high, and it will discharge cold air to bring the interior temp down.....as it approaches the 75 logarithm, the speed will slow down and the temp discharged will be less cool.....

Notice I said logarithm, not temperature.....When you set your system for 75, you are not going to get 75 degree air...this is not a thermostat....75 is the midpoint of your temp control....when you are on 75, and in "AUTO" MODE, the system attempts to maintain mid temp of the system(just like the old manual system where you would slide the lever to the middle).....

However, if you manually change the blower speed, the system comes out of auto mode, it will constantly blow at the speed you have selected, and if it is too warm, just lower the setting one degree at a time until the desired temp comes out......

If you stick a thermometer in one of the registers, go into vent and econ mode(this mode shuts the compressor off), at 65 you will probably get whatever the outside air actually is......if outside air is 80F, that is probably what you will get out of the registers....

Wow. Thank you. Great explanation on the functionality involved. It is a dual system. At 65, it remains very warm, even if in the teens and 20's outside. I have noticed that when it is fully shut off (I often shut it off), there is still some very warm air leaking through below the dash from the heat zone area (black box). Not sure what it is really called. Just seems to leak around the edges. Definitely not the outside air temp at 65. Kind of wondering if there is some type of adjustment on it.

Makes me long for a cable running to a valve in a heater hose. Slide the lever over and the heat is perfect.

AT the 65 setting, it should not be warm......is it just warm on one side, and cool on the other?

Code might be set in the control head but it will take a GM scan tool to read it and also read the interior temp sensor and the "actual" position of the driver and passenger temp doors.....