1999 Buick - Auto Temp Control

[Princeton Auto]

Vehicle is equiped with dual temp. controls. Driverside temperature control does not move to the cold. Replaced actuator (motor) with 2 different new motors. Replaced controller twice--both used. Checked continuity of the wiring--good. If I unplug the controller and plug it back in, the actuator moves to the cold but only one time. It will move from hot to medium but not to cold after the first complete sweep.

I can manually operate the motor by disconnecting the controller and adding the ground and power to the appropriate circuit. But the controller cannot move he motor to the cold.

I have followed the test procedure, it indicates the controller is the problem, but the same problem with 3 controllers??? I don't buy it.

I have spent hours checking everything multiple times, I must be missing something.

[steven kiser]

did you scan for codes? i can't remember exactly which years but there were a few where if there was a climate control issue the system would default until the codes cleared. i believe there is a cabin temp sensor. if this is shorted it will cause issues. with the scanner attached look at the cabin temp.

[Princeton Auto]

I will scan again to make sure. I do know the cabin temp. sensor is operating normally. Checked it for operation previously. Thanks for the tip.

[Princeton Auto]

Vehicle is repaired. Scanned HVAC and there were no codes present. I controlled the temperature actuators with the scanner and they both worked properly. Disconnected the scanner and system functioned normally. Released to customer.

[steven kiser]

ahhhhh, chicken bones and prayer candles.......................