Ventilation - A/C Temperature Control acting up

[wildspeed]

2006 Vue 3.5L

Couple of days ago, the temperature control knob started not to work properly.
Sometime it wouldn't set the temperature accordingly to the position.
Would go from freezing a/c to full heat when moved pass the middle point and will stay on full heat even when returned to coldest position.
Will eventually go back to work after multiple try.

[fdryer]

I don't know if we share ('03 L300) the same auto climate control system - 5 buttons across the top, two dials on either side and 2 bottom buttons with a small grille between them. An lcd displays functions. If yours is auto climate control, it may be either an intermittent issue or announcing its demise.

Mine began with cold temperatures making the temperature dial unresponsive, slow in displaying changes until the cabin warmed up. This started well after 10 yrs of ownership. A replacement seems to correct that problem but I noticed temperature dialing is beginning to show itself this winter. In cold temps I dial up maximum heat before shutting the engine down so the heater door is directing incoming air thru the heater on the next startup. Once warmer inside the car the dial acts normal. Since this auto climate control system has its own mini computer, controlling a blend and mode door, the actuators are controlled by this climate control module. The small grille is for the air temperature sensor to monitor cabin temps for the system to adjust the blend door - mixing outside, ac and heater according to whoever sets the hvac system. Auto temperature regulation was never great with wide swings sometimes.

If you have a cabin air filter, was it replaced as needed?

[far2grumpy]

Originally Posted by wildspeed

2006 Vue 3.5L

Couple of days ago, the temperature control knob started not to work properly.
Sometime it wouldn't set the temperature accordingly to the position.
Would go from freezing a/c to full heat when moved pass the middle point and will stay on full heat even when returned to coldest position.
Will eventually go back to work after multiple try.

The temp knob controls signals to the temp actuator. Actuators are accessible and replaceable by removing glove compartment.

You could try a simple calibration first with these steps from service manual.

Calibrate the mode actuators by simultaneously pushing the A/C and RECIRC buttons on the HVAC control module 3 times each, within 2 seconds of initial push.

1. The A/C and RECIRC button LED's will flash while this calibration is taking place.

2. The calibration will take anywhere between 10 to 30 seconds depending on battery voltage.

3. LEDs will quit flashing when calibration is complete.

4. Cycle ignition and verify proper operation.


I'll email extracts to replace the actuator if calibration fails to fix problem. Send email address by private message.

Actuators are commonly available - I see Rock Auto has for around $60 before shipping and Amazon has several different actuators ranging from $20 to $60.

[wildspeed]

Originally Posted by fdryer

I don't know if we share ('03 L300) the same auto climate control system - 5 buttons across the top, two dials on either side and 2 bottom buttons with a small grille between them. An lcd displays functions. If yours is auto climate control, it may be either an intermittent issue or announcing its demise.

Mine began with cold temperatures making the temperature dial unresponsive, slow in displaying changes until the cabin warmed up. This started well after 10 yrs of ownership. A replacement seems to correct that problem but I noticed temperature dialing is beginning to show itself this winter. In cold temps I dial up maximum heat before shutting the engine down so the heater door is directing incoming air thru the heater on the next startup. Once warmer inside the car the dial acts normal. Since this auto climate control system has its own mini computer, controlling a blend and mode door, the actuators are controlled by this climate control module. The small grille is for the air temperature sensor to monitor cabin temps for the system to adjust the blend door - mixing outside, ac and heater according to whoever sets the hvac system. Auto temperature regulation was never great with wide swings sometimes.

If you have a cabin air filter, was it replaced as needed?

Different system, thank you

[wildspeed]

Originally Posted by far2grumpy

The temp knob controls signals to the temp actuator. Actuators are accessible and replaceable by removing glove compartment.

You could try a simple calibration first with these steps from service manual.

Calibrate the mode actuators by simultaneously pushing the A/C and RECIRC buttons on the HVAC control module 3 times each, within 2 seconds of initial push.

1. The A/C and RECIRC button LED's will flash while this calibration is taking place.

2. The calibration will take anywhere between 10 to 30 seconds depending on battery voltage.

3. LEDs will quit flashing when calibration is complete.

4. Cycle ignition and verify proper operation.


I'll email extracts to replace the actuator if calibration fails to fix problem. Send email address by private message.

Actuators are commonly available - I see Rock Auto has for around $60 before shipping and Amazon has several different actuators ranging from $20 to $60.

Thank you.
Tried the calibration, worked after doing it, but issue came back the next time driving out.
Will get a replacement actuator.