A/C - Insufficient Cooling While Driving

88cadillac13

Bulletin No. T-89-39
File in Group 1
Number 58
Corp. Ref. No. 811212
Date Nov. 1988
SUBJECT: INSUFFICIENT A/C COOLING WHILE DRIVING

MODELS AFFECTED: 1988-1989 BROUGHAMS

Some 1988-1989 Broughams may experience a condition of insufficient A/C cooling while driving in stop-and-go traffic in hot, humid climates. This condition may be caused by the ECM PROM calibration. The production calibration disengages the A/C compressor clutch with changes in throttle angle, instead of only during a wide open throttle maneuver (as in past model years).

Should the insufficient A/C cooling only occur at an extended idle, refer to Serviceman Bulletin T-88-131.

To repair a condition of insufficient cooling in stop-and-go traffic use the following procedure:

1. Verify that the A/C system has the proper charge of Refrigerant 12. With ambient temperature above 60~F:

^ Start engine and allow to warm up.
^ Open hood and body doors.
^ Set CCP at 60~F and "auto" setting.
^ "Hand feel" the temperature of the evaporator inlet pipe after the orifice tube and accumulator surface with the compressor engaged.
^ The temperature of both should be the same and both should be the same amount cooler than the ambient temperature.
^ If not, refer to Section 1C of the Service Information Manual for diagnosis.

2. Install a scan tool and record the ECM PROM I.D. If the ECM PROM I.D. is 7524 (Federal) or 7528 (California), install the revised ECM PROM from the chart below:

Emission Service
Year System MEM-CAL PN

1988-1989 Federal 16122177
1988-1989 California 16132056

3. If the condition is still present after installing the MEM-CAL, refer to ECC Functional Test in Section 1C of the 1988 or 1989 Service Information Manual.

For warranty purposes use Labor Operation J6364 at .6 hour.