A/C - No Cooling Fan Operation In Defrost Mode
89pontiac18Bulletin Number: 89-1-11
Reference Number: 931103
Publish Date: 6/89
Subject: NO COOLING FAN OPERATION IN DEFROST MODE (INSTALL A/C PRESSURE SWITCH)
Models
Affected:
1984-1989 FIREBIRD MODELS WITH 5.0L
ENGINE (TYPICAL) L69 & LG4:
WIRING CIRCUIT L69 & LG4 ENGINE:
This bulletin cancels and replaces 88-1-18 issued 6/88.
Some 1984 through 1989 Firebird models with A/C and the above V8 engines may have condensation on the windshield, compressor noise, rough or low engine idle slow when the A/C system is in the DEFROST mode, during idle or city traffic driving.
The probable cause for any and all of these conditions is that the engine cooling fan does not run in the DEFROST mode. This may be addressed by installing an A/C pressure switch in the A/C system and wiring it to the cooling fan circuit, using the following two sets of service parts and procedures as specified.
The first set of parts should be used when working on the 1984-85 vehicles with the L69 engine and the 1986-87 vehicles with the LG4 engine.
Part Number Part Name
14089590 A/C Pressure Switch
12058922 Switch connector with
pigtail wires colored dark blue and black
Procedure:
1. Disconnect the negative battery cable.
2. Install the A/C pressure switch in the valve fitting of the A/C pipe from the evaporator to the condenser (As shown in Figure 1).
3. Locate and pull the cooling fan switch wire out of the conduit on the lower right hand side of the engine. The cooling fan switch is located at the rear right hand side of the engine, between # 6 and # 8 cylinders, above the starter motor solenoid.
4. Splice the dark blue wire of pressure switch connector to the cooling fan switch wire. Tape the splice and reinstall the cooling fan switch wire in the conduit. Cut a small notch in the conduit for the breakout point of the dark blue wire to the pressure switch and tape the conduit on each side of the breakout point.
5. Install a ground wire ring terminal on the end of the black wire of the connector and attach it to the sheet metal body ground connection located above pressure switch near the battery.
6. Reconnect the negative battery cable.
7. Start the engine, put the A/C control selector in DEFROST mode and FULL COLD and check for cooling fan operation.
Labor Operation Number: T1345
Labor Time: 0.3 Hours
WIRING CIRCUIT L69 & LG4 ENGINE:
L03 ENGINE:
The following second set of parts and procedure are to be used when working on the 1988-89 vehicles with the L03 engine.
Part Number Part Name
14089590 A/C Pressure Switch
12090235 Wire Assembly - A/C
Pressure Fan Switch
Parts are expected to be available on June 12, 1989. Until then normal part orders will not be accepted by GMSPO. Only verifiable emergency VIP orders will be accepted. SPO will make every effort to obtain parts. All parts will be shipped premium transportation at dealer's expense. All other order types will be canceled as incorrectly ordered while the 400 control is in place.
Procedure:
1. Disconnect the negative battery cable.
2. Install the A/C pressure switch in the valve fitting of the A/C pipe from the evaporator to the condenser (as shown in Figure 3).
3. Connect the wire assembly to the engine harness and the A/C harness and route the wire assembly around the A/C accumulator and connect to the pressure switch (as shown in Figure 3).
4. Reconnect the negative battery cable.
5. Start the engine, put the A/C control selector in DEFROST mode and FULL COLD and check for the cooling fan operation.
Labor Operation Number: T1462
Labor Time: 0.3 Hours
The VIN breakpoints for 1989 vehicles with (VIN E) engines that already have A/C pressure switch and wire assembly are as follow:
Pontiac - KL251704