All 1992-1993 DeVilles and Fleetwoods up to VIN breakpoint P425051 may experience a whistling-type noise when the air conditioning system is in a recirculate mode. The condition is most prevalent at speeds of 45-60 mph (75-100 kph) and maybe mistaken for a wind noise from the lower center section of the windshield.
To diagnose this condition set A/C controls to "Auto" 60 degrees Fahrenheit Drive the vehicle at 45-60 mph (75-100 kph) and listen for the whistle noise. Turn the A/C controls to "OFF". If whistle stops after the A/C is turned off, then noise is being generated from outside air/recirculate door (air inlet valve).
To correct this condition install a J- clip, P/N 52466011, on the air inlet valve stop using the following procedure:
1. Lower left and right hush panels to gain access to air inlet actuator.
2. Locate the outside air recirculation valve vacuum actuator.
3. Attach clip, P/N 52466011, to actuator "stop" located on the left side of the case to hold valve from being fully closed. Do not fully seat the clip. It should protrude approximately 1/8 inch. Refer to Figure 1.
4. Reinstall hush panels.
Parts are currently available from GMSPO.
For warranty purposes use Labor Operation T6682 at .2 hour.
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.