Some 1993 Fleetwoods (RWD) may experience higher than normal blower speeds while in heater, defroster, and air conditioning settings.
This may be caused by the heater shut off door which may have failed and fallen into the heater air stream, restricting flow, requiring higher blower speeds in the automatic system.
The repair procedure is to remove the broken heater shut off door as follows, which will allow proper temperature and flow of air.
1. Remove A/C module lower evaporator case per Service Information Manual, Section 1B1. Front screw "A" may be hidden by carpet and difficult to access. Use of a 7mm flex head socket may be helpful. Refer to Figure 1 for attaching points.
2. Locate heater shut off door in heater case. Refer to Figure 2.
3. If heater shut off door appears loose and NOT spring loaded, verify that it is broken by trying to cycle door. Do this by toggling temperature selector switch from full cool (60 degrees Fahrenheit) to full warm (90 degrees Fahrenheit).
4. Pull heater shut off door hinge arm out of its socket at the end closest to the rear of the vehicle.
5. Remove heater shut off door by reaching through case opening and pushing the broken end of the door into the heater case cavity. Rotate the door while removing it through case opening.
6. Install/connect A/C module lower evaporator case per Service Information Manual, Section 1B.
For warranty purposes use Labor Operation T3300 at .9 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.