System Diagnosis

Refer to SCHEMATIC DIAGRAMS/ELECTRICAL AND ELECTRONIC DIAGRAMS, for wiring schematics.

Primary Coolant Fan Does Not Run

1. With ignition switch in RUN position, ground terminal B (white/black) of ALDL connector. If primary coolant fan runs, problem is ECM related.
2. If primary coolant fan does not run, turn ignition switch to RUN position and ground terminal A9 (dark green/white) at ECM with fused jumper. If primary coolant fan runs, problem is ECM related.
3. if primary coolant fan does not run, turn ignition switch to RUN position, leave fused jumper connected as in step 2, disconnect primary coolant fan relay connector and measure voltage from terminal 3 (red) to ground. If no voltage is present, check for open in red wire.
4. If battery voltage is present, turn ignition switch to RUN position, leave fused jumper connected as in step 2 and measure voltage between terminals 3 (red) and 1 (dark green/white). If no voltage is present, check dark green/white wire for open.
5. If battery voltage is present, disconnect primary coolant fan relay connector and measure voltage from terminal 2 (red VIN D & X), (brown/white VIN T) or (pink/black early production regal VIN T) to ground at RS electrical center. If no voltage is present, check brown/white, red or pink/black wire for open.
6. If battery voltage is present, disconnect primary coolant fan relay connector and connect a 20 amp fused jumper between terminals 3 (red) and 5 (black/red) at RS electrical center. If primary coolant fan runs, check for satisfactory contact between primary coolant fan relay and RS electrical center. If satisfactory, replace primary coolant fan relay.
7. If primary coolant fan does not run, leave fused jumper connected as in step 6, disconnect primary coolant fan connector and measure voltage from terminal B (black/red) to ground. If no voltage is present, check black/red wire for open.
8. If battery voltage is present, leave fused jumper in place as in step 6 and measure voltage between terminals B (black/red) and A (black).
9. If no voltage is present, check black wire for open.
10. If battery voltage is present, check primary coolant fan connector terminals for cleanness and tightness and, if satisfactory, replace primary coolant fan.

Secondary Coolant Fan And/Or Generator Coolant Fan (VIN X) Does Not Run

1. With ignition switch in RUN position, ground terminal A3 (dark blue/white) at ECM with fused jumper. If coolant fan runs, problem is ECM related.
2. If coolant fan does not run, leave fused jumper connected as in step 1, disconnect secondary coolant fan relay connector, turn ignition switch to RUN position and measure voltage at RS electrical center terminal 2 (brown) or (pink/black early production Regal VIN T) to ground. If no voltage is present, check brown or pink/black wire for open.
3. If battery voltage is present, leave fused jumper connected as in step 1, turn ignition switch to RUN position and measure voltage between terminals 2 (brown) or (pink/black early production Regal VIN T) and 1 (dark blue/white). If no voltage is present, check dark blue/white wire for open.
4. If battery voltage is present, measure voltage between terminal 3 (red) and ground. If no voltage is present, check red wire for open.
5. If battery voltage is present, disconnect secondary coolant fan relay connector and connect 20 amp fused jumper between terminals 3 (red) and 5 (black/red) at RS electrical center.
6. If secondary and/or generator coolant fan (VIN X) runs, check secondary coolant fan relay connector terminal contact at RS electrical center. If satisfactory, replace secondary coolant fan relay.
7. If secondary and/or generator coolant fan (VIN X) does not run, leave fused jumper connected as in step 5, then disconnect secondary and/or generator coolant fan connector (VIN X) and measure voltage between terminal B (except VIN X) or terminal A (VIN X) (black/red) and ground. If no voltage is present, check black/red wire for open.
8. If battery voltage is present, leave fused jumper connected as in step 5 and measure voltage between terminals B (black/red) and A (black) or terminals A (black/red) and B (black) (VIN X). If no voltage is present, check black wire for open.
9. If battery voltage is present, check suspect coolant fan connector and ensure terminals are clean and tight. If satisfactory, replace suspect coolant fan.

Primary Coolant Fan Runs Continuously With Engine Coolant Cool & A/C Mode Selector Off

1. Disconnect primary coolant fan relay at RS electrical center, turn ignition switch to RUN position and connect test lamp between terminals 3 (red) and 1 (dark green/white).
2. If lamp does not illuminate, replace primary coolant fan relay.
3. If lamp illuminates, check dark green/white wire for short to ground. If wire is satisfactory, problem is ECM related.

Secondary Coolant Fan And/Or Generator Coolant Fan Runs Continuously With Engine Coolant Cool & A/C Mode Selector Off

1. Disconnect secondary coolant fan relay at RS electrical center, turn ignition switch to RUN position and connect test lamp between terminals 3 (red) and 1 (dark blue/white).
2. If lamp does not illuminate, replace secondary coolant fan relay.
3. If lamp illuminates, check dark blue/white wire for short to ground. If wire is satisfactory, problem is ECM related.