A/C - Recirculation Mode Explained
GMC NUMBER: 92-1B-94GROUP: 1B Air Conditioning
DATE: June, 1992
CORPORATE
NUMBER: 261202R
SUBJECT:
AIR CONDITIONING PERFORMANCE DIAGNOSIS
MODELS:
1991-92 C/K AND TOPKICK/KODIAK VEHICLES WITH AIR CONDITIONING (RPO C60 OR C69)
Some owners of 1991-92 C/K and TopKick/Kodiak vehicles may 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.