SERVICE MANUAL UPDATE A/C CLIMATE CONTROL REVISED DIAG.

SUBJECT: ELECTRICAL SYSTEMS MANUAL UPDATE - SECTION:CLIMATE CONTROL DUAL AIR CONDITIONING (CJ2) (REVISED ON-BOARD DIAGNOSIS PROCEDURE)

MODELS AFFECTED: 1991 PARK AVENUE/PARK AVENUE ULTRA

The On-Board Diagnostics for Dual Air Conditioning (CJ2) on page 384 of the 1991 Park Avenue/Park Avenue Ultra Electrical Systems Manual have been revised. In ECC OVERRIDE, the "Comments" portion of 119 F: Update Ambient Temperature to Actual lacks the procedure for immediate updating of ambient temperature sensor input.

"Comments" following "Output Number 119 F" should read: Push Warm or Cool Button for Immediate Update. Without performing this procedure, the sensor itself may take as long as six hours to update its input.

Please update your Electrical Systems Manual accordingly.

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.