This is actually a common problem with these vehicles. There are a couple GM service bulletins that address this concern. What has happened is the A/C control module has detected a problem with the temperature door actuator. When this happens, it defaults to the full hot position. There is a new program for the A/C module that will help with this condition, but until you can take it to a dealership for the reprogram, there are a couple things you can try to get the drivers side working. The first thing to try is to pull the HVAC fuse located in the under hood fuse block, wait about 1 minute and put it back in. Then start the vehicle, when turn the key on, the HVAC will rehome all actuators. This means that they will all be made to go to the full hot and full cold position and they will cycle from blowing out of the floor then to defrost. After this your drivers side may return to the desired position. If, while they are rehoming, you notice that the drivers side does not change at all, then you may need a new drivers side temperature actuator. In most cases the reprogram will fix what is happening. I will list the bulletin that addresses this for you to read through and get a better understanding of what is happening. If you need more help, just ask.
#06-01-38-003: Intermittent Ticking Noise from I/P, Poor A/C Performance, HVAC DTCs B0229, B0414, B0424, B3770, (Reprogram HVAC Control Module) - (Apr 27, 2006)
Some customers may comment on one or more of the following concerns:
This condition may be caused by the Heating, Ventilation and Air Conditioning (HVAC) actuators that may hunt for the correct commanded position. This cycling may cause a clicking or ticking noise.
An overtravel of the HVAC system control doors may cause one or more of the concerns listed above. If an overtravel occurs, a Diagnostic Trouble Code (DTC) will be set, and the door will go to a preset default position. When a system door defaults, that door will stay at the default position until the DTC is cleared. After the DTC is cleared, the door will operate properly until the overtravel condition re-occurs.
The following table lists the HVAC system doors and the DTC associated with it.
Air inlet door (recirculation door)
Left temperature door
Right temperature door
Front system mode door
Technicians are to perform the normal diagnostic procedures in SI for these concerns. If diagnostics show that the HVAC system door(s) travel below 5 counts (out of the lower range) or above 250 counts (out of the upper range), then update the software calibrations in the HVAC control module. The new calibrations were made available to dealerships as part of TIS2000 incremental satellite update version 2.5, which was broadcast to dealers in February 2006.
The new calibrations have been updated to compensate for the actuator overtravel condition, the actuator hunting and the ticking/clicking noises. The new calibrations effectively eliminate the codes listed above, the default position of the doors associated with the DTCs and opens up the feedback position value. The new calibrations should not be used unless the vehicle has one or more of the customer concerns listed above or a DTC listed above has been set. The new calibrations will not correct any other DTC or A/C system performance concern.