Poor Driver’s Side A/C Performance

The air conditioning may blow warmer on the driver’s side of the vehicle on some 2019-2020 Silverado 1500 and Sierra 1500 models built at the Silao assembly plant (the plant is identified by a G in the 11th position of the VIN).

On affected vehicles, the A/C pressures will be lower than normal. For example, the low side may be 15-25 PSI (103-172 kPa) while the high side may be 140-160 PSI (965-1103 kPA). A check of the system for a low refrigerant charge should indicate that the system is full and no leaks should be found.

In addition, a temperature test of the refrigerant lines will show both the inlet and outlet lines at the condenser to be similar and very hot. The temperature across the condenser’s cooling fins will be near ambient temperature.

The cause of these conditions could be the A/C condenser internally bypassing due to a mispositioned block off plate. If the block off plate is out of position, the refrigerant does not flow through the condenser’s cooling fins. As a result, hot refrigerant entering the condenser bypasses the cooling fins and exits the condenser before the refrigerant is cooled down and returned to a liquid state.

If these conditions are found, the A/C condenser (Fig. 22) will need to be replaced. Refer to the appropriate Service Information for A/C condenser replacement.


Fig. 22


– Thanks to Jim Will

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