Buick GL8 air condition not working and outside temperature inaccuracy

In this article we will share a real case about how to solve buick GL8 air condition not work and out side temperature display imprecisely on dashboard.

Car information: Buick GL8 3.0 MPV 2007,have 150,000 kilometers.

Symptom Problem: There is a mistake information of outside temperature display on dashboard and air condition not work.

Test and analysis: we make a comprehensive inspection on air condition system to confirm it’s fine. High pressure of refrigerant is 2.3MPa, and low pressure is 0.3 MPa, when the engine is idling. Both pressure are high and air condition have poor cooling. Detect air condition control unit, no fault code exist.

We drive the car to test personally. The air condition work properly and inside temperature cool fall quickly, it show outside temperature at 37℃.But when car in low speed, the air condition be worst. Inside temperature risen quickly. And outside temperature at 52℃. This symptom disappear when the car in high speed.

We find the outside temperature sensor is installed before engine radiator, it can be seen that the high temperature display at low speed is related to the high air temperature in the engine compartment. This anomaly of temperature also gives the reason for the high pressure of the refrigerant. The engine compartment temperature is high, indicating that the engine cooling system have problems. But we observed temperature of water when we driving, and did not find abnormal. Analysis of the engine compartment air temperature rise is due to the temperature of the radiator surface, indicating that the temperature of the coolant higher than normal. After the temperature of the coolant increases, the temperature difference with the surrounding air of the vehicle increases, which improves the heat dissipation effect of the radiator to a certain extent, but the condition of the air conditioner condenser becomes very unfavorable. In this case the cooling system can meet the cooling requirements of the engine, indicating that the coolant heat exchange process is normal, the problem should be in the cooling fan air volume on the.

Solution: Replace the cooling fan. We driven car again and problem have troubleshooted.