A/C - Performance Diagnosis Use of Recirculation Mode
Number: 92-217-1ASection: 1A
Date: JUNE 1992
Corporate Bulletin No.: 261202
ASE No.: A7
Subject:
AIR CONDITIONING PERFORMANCE DIAGNOSIS
Model and Year:
1991-92 C/K TRUCKS
Some owners of 1991-1992 C/K comment that their air conditioner is not cooling sufficiently. When investigating air conditioning performance comments, especially if a performance test leads to a diagnosis of no trouble found, be sure the customer understands the intended use of the recirculation ("RECIR") feature.
Selecting recirculation causes the Air Conditioning system to draw air from the passenger compartment rather than from outside the vehicle. As already cooled air begins to circulate through the air conditioner it becomes increasingly easier to dehumidify and cool. This increase in cooling ability can cause center duct temperatures to be 10 to 15 degrees F (9 to 12 degrees C) cooler at 50 MPH (80 km/hr) assuming an ambient temperature of 100 degrees F (38 degrees C) and 40 percent humidity.
If a customer desires maximum Air Conditioning performance, be sure they understand the operation of the recirculation ("RECIR") feature.