Chevrolet Repair Questions? Ask a Chevy Mechanic for Answers ASAP
the problem may be the fan relay
The electric cooling fan operates when the engine cooling temperature exceeds a certain value. The cooling fan on this engine is controlled by the Powertrain Control Module (PCM) . The cooling fan has one speed. The PCM turns the cooling fan on by grounding the coil of the cooling fan relay when certain conditions are met. When the A/C is requested, the cooling fan will also be turned on.
The engine cooling fan control is partitioned between the PCM and the BCM via class 2. The main algorithm control resides in the BCM. The BCM sends a fan speed command to the PCM. The PCM processes this command along with its own fan request. The PCM determines what the actual fan speed should be.