Q: We recently bought a 2004 Yukon SLT and are having problems with the air conditioning. I could be driving along with a/c on, and then all of a sudden the a/c on the driver's side will turn extremely hot. If I stop the vehicle completely and turn it off and back on, this often corrects the problem for a bit; but the driver's side will eventually turn warm again without any advance warning. I've had the vehicle checked twice, to no avail. Can you help me resolve this?
A: The problem is a worn driver-side temperature actuator. When the actuator wears, the feedback to the control module goes out of limits. When this occurs, the control module forces the actuator into a default mode (full heat). GM has developed updated software to fix this condition; please refer to this bulletin.
The dealer will typically charge $60-100 for this software upgrade, but it's much cheaper than replacing the actuator. This also prevents future problems with the other actuators in the system (there are four).
-- Answer from Dave Nova, GMC technician on JustAnswer.
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