Why does my heater-a/c not power off or let me change the fan speed?

What is your question?

When I turn the car on, the heater-a/c comes on but when I try to adjust the fan speed or put on auto, it will not change. When I press the power button, it shuts off but immediately comes back on with the fan speed on high. I can not turn it off or adjust the fan speed. I can however change the temperature and the position from vent to feet and to defrost.

How long has your 2003 Cadillac CTS had this problem?

About 2 weeks