For 1990-2009 cars

# INSUFFICIENT A/C COOLING AT IDLE

#### MODELS AFFECTED: 1985 AND 1986 DE VILLES, FLEETWOODS, AND FLEETWOOD SEVENTY FIVE LIMOUSINE

This bulletin supercedes bulletin T-85-86 which should be destroyed.

Some 1985 and 1986 De Villes, Fleetwoods and Fleetwood Limousines may experience insufficient air conditioning cooling while driving at low speeds in high ambient temperatures and high humidity. This condition may be caused by insufficient air flow across the condenser.

To correct this condition, a new BCM PROM (refer to chart below) and cooling fan shroud (P/N 22040876) have been released. The BCM PROM was a mid-year production change on 1986 De Villes after broadcast number 311366 and 1986 Fleetwood Limousines after broadcast number 311474. To install these components, proceed as follows:

#### BCM PROM INSTALLATION

Check the BCM PROM calibration using F.8.0 BCM data display diagnostic parameter P.3.1 (BCM PROM I.D.). If the BCM PROM I.D. does not match the value listed in the chart below, the PROM should be replaced with the part number shown. After verifying or installing the PROM, proceed with the "ECC System Check" outlined in the Service Information Manual.

BCM PROM FOR IMPROVED A/C PERFORMANCE ------------------------------------- Application PROM I.D. Broadcast Code Part Number ----------- --------- -------------- ----------- 1985 FWD De Ville 14 HRY 1228026 and Fleetwood with 4.1 V-8 Engine

1985 FWD De Ville 114 HRZ 1228024 and Fleetwood with 4.3 Diesel Engine

1985 FWD Fleetwood 204 HSA 1228025 "75" Limousine

1986 FWD De Ville 20 AAPT 16062532 and Fleetwood with 4.1 V-8 Engine

1986 FWD Fleetwood 220 AAPU 16062546 "75" Limousine

#### FAN SHROUD INSTALLATION

1. Disconnect left fan electrical connector.

2. Remove and discard the four (4) bolts fastening left fan brace to radiator.

3. Remove fan assembly. Discard four (4) isolating washers, Figure 1.

4. Remove fan blade from shaft, and fan motor from brace. Discard brace.

5. Attach fan motor to shroud (P/N 22040876) and reinstall fan blade.

6. Install fan shroud assembly to radiator using new bolts (P/N 20351035) Figure 2.

7. Reconnect fan electrical connector.

For warranty purposes, use Operation Number N4801 at .4 hour for BCM PROM replace and Operation Number T6160 at .4 hour for shroud installation.

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.