Automatic dual control issue

Oldsmobile_Kid_1Oldsmobile_Kid_1 Member Posts: 1
edited November 2018 in Buick
My 2004 Lesabre Limited has an issue with the temperature control on the driver's side. The controls on the passenger side seem to work just fine, but the temperature on the drivers side will not control. It seeems to bypass the heater core in cooler weather and evaporator in the warm months. I have replaced the temperature actuator, but this did not help.
The system has heat and cooling, just not on the driver's side. Could this be one of the temperature sensors or the control module under the dash on the driver's side? Any help would be appreciated!


  • imidazol97imidazol97 Member Posts: 26,795
    edited November 2018
    I'm going to ask the dumb questions, so bear with me. I had a 2003 leSabre along with two of earlier generation leSabres.

    Are you sure the temperature blend door actuator was NOT working. This requires taking off the plastic panel under driver side and looking up at the mode door and blend door while someone else operates the temperature settings with engine on and coolant hot.

    There is usually a white part to the rotor on the electric motor that you can see turn, one way and then other way.

    Without checking diagrams I believe both motors are on the driver side. Did you replace the right one?

    There's a slight possibility the flap inside the HVAC box has broken and is not moving even if the actuator is moving.

    Was the new one operating after replacement? I do not recall if there is a reset procedure for the car that resets the control module, the brain. On start up the brain should cycle the motor to determine its full cycle range of hot to cold, if it operates like the 92-99 version did.

    I'll add a diagram for the dual control unit when I find one, or I'll take of pic out of factory service manual.

    If that didn't fix the operation, I'd do a switch next. I don't know what the replacement module in the dash that has the switches costs from a recycle yard or picknpull.

    Because of the costs to guess at parts, you might be served moneywise if a repair shop has a real Tech II or replacement that can see if the switch is giving input to the control module. And it could check the module.
    Dealer fee might be worth it other than they wouldn't want to get a used unit to replace anything.

    Check for parts. Although be very careful about their labeling. I've found their HVAC parts to be mislabeled as to what they do for individual product brands.

    2014 Malibu 2LT, 2015 Cruze 2LT,

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