| Table 1: | Electric Cooling Fan Functional Check |
| Table 2: | Electric Cooling Fan Table #1 |
| Table 3: | Electric Cooling Fan Table #2 |
| Table 4: | Electric Cooling Fan Table #3 |
Refer to Engine Controls Schematics
Coolant Fans
Circuit Description
Power for the fan motors is supplied through the Cool Fan 1 MaxiFuse®
30A and the Cool Fan 2 MaxiFuse® 30A in the
Underhood Accessory Wiring Junction Block Label
. The cooling fan relays
are energized when current flows from the 2 Maxifuses®
through the relay coils to ground through the powertrain control module
(PCM). The Cool Fan 1 Relay Control Circuit is grounded for low speed
fans operation. The Cool Fan 1 Relay Control Circuit and the Cool Fan
2 Relay Control Circuit are both grounded for high speed fans operation.
During low speed fans operation the PCM supplies a ground path for
the Cool Fan 1 Relay. This closes the Cool Fan 1 Relay contacts, allowing
current to flow from the
Underhood Accessory Wiring Junction Block Label
through the relay contacts
to the Engine Coolant Fan Motor 1 RH. During low speed operation, the
ground path for the Engine Coolant Fan Motor 1 RH is through the Coolant
Fan 1 Relay and the Engine Coolant Fan Motor 2 LH. The result is a series
circuit with both cooling fans running at low speed.
During high speed cooling fan operation the PCM supplies a ground path
for the Cool Fan 1 Relay. The PCM also supplies a ground path for the Cool
Fan Relay and the Cool Fan 2 Relay. This closes all 3 cooling fan relays.
During high speed fans operation, both the Engine Coolant Fan Motor 1
RH and the Engine Coolant Fan Motor 2 LH are supplied current from the
Underhood Accessory Wiring Junction Block Label
and each cooling fan has its own ground path.
Test Description
The numbers below refer to numbers on the diagnostic table:
-
The PCM will enable the engine cooling fans when certain Diagnostic Trouble Codes are set. Go to applicable DTC Table first before proceeding with this table.
-
Allow engine coolant temperature to cool below 100°C (212°F) before proceeding with diagnosis.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain OBD System Check? | -- | ||
Are any DTCs set? | -- | Go to applicable DTCs | ||
Are the cooling fans off? | 100°C (212°F) | Go to Cooling Fan table #1 | ||
4 | With a scan tool, command Low Speed Fans on. Are both cooling fans on? | -- | Go to Cooling Fan table #2 | |
5 |
Important: : Allow a 3-5 second delay before determining if the fans have switched from low to high speed. With a scan tool, command High Speed Fans on. Do both cooling fans switch to high speed? | -- | Go to Cooling Fan table #3 | |
6 |
Are the cooling fans on? | -- | ||
7 | Turn on the A/C. Are the cooling fans on? | -- | System OK | |
8 | Does the scan tool display A/C request as YES? | -- | Go to Cooling Insufficient - Air Conditioning (A/C) System in Heating, Ventilation, and Air Conditioning | |
9 | Does the scan tool display A/C request as YES? | -- | Go to Powertrain Control Module Controlled Air Conditioning (A/C) Circuit Diagnosis | Go to Cooling Insufficient - Air Conditioning (A/C) System in Heating, Ventilation, and Air Conditioning |
10 |
Important: : The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming .Is the action complete? | -- | System OK | -- |
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Cooling Fan Functional Check? | -- | Go to Cooling Fan Functional Check | |
2 | Disconnect Cool Fan 1 Relay. Are both fans off? | -- | ||
3 | Disconnect Cool Fan Relay. Are both fans off? | -- | ||
4 |
Does the test lamp illuminate? | -- | ||
5 | Probe terminal A of the left fan connector using a test lamp that is connected to a known good ground. Does the test lamp illuminate? | -- | ||
6 | Probe the High Speed Fans control circuit (473) at the Cool Fan Relay
connector in the
Does the test lamp illuminate? | -- | ||
7 |
Is the test lamp still illuminated? | -- | ||
8 | Probe the Low Speed Fans Control circuit (335) at the Cool Fan 1 Relay connector using the test lamp that is connected to battery positive voltage. Does the test lamp illuminate? | -- | ||
9 |
Is the test lamp still illuminated? | -- | ||
10 | Repair the RH fan feed circuit (409) for a short to voltage. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Cooling Fan Functional Check | |
11 | Repair the LH fan feed circuit (532) for a short to voltage. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Cooling Fan Functional Check | -- |
12 | Repair the short to voltage in the Cool Fan Relay feed circuit (504). Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Cooling Fan Functional Check | -- |
13 | Replace the Cool Fan 1 Relay. Did you complete the repair? | -- | Go to Cooling Fan Functional Check | -- |
14 | Repair the High Speed Fans Control circuit (473) or the Low Speed Fans Control circuit (335) for a short to ground. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Cooling Fan Functional Check | -- |
15 | Replace the Cool Fan Relay. Did you complete the repair? | -- | Go to Cooling Fan Functional Check | -- |
16 |
Important:: Program the replacement PCM. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Did you complete the repair? | -- | Go to Cooling Fan Functional Check | -- |
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Cooling Fan Functional Check? | -- | Go to Cooling Fan Functional Check | |
2 | Did either fan turn on when Cool Fan 1 Relay was commanded on? | -- | ||
3 |
Did the other fan turn off? | -- | ||
4 | With the Low Speed Fans Commanded ON, Disconnect Cool Fan Relay. Did the left fan turn off? | -- | ||
5 |
Does the test lamp illuminate? | -- | ||
6 | Probe both feed circuits (342) at the Cool Fan 1 Relay Connector using a test lamp that is connected to ground. Does test lamp illuminate for both circuits? | -- | ||
7 |
Important: : Leave jumper in place for remainder of this table. Connect a fused jumper wire between the switch feed circuit (342) and the LH fan feed circuit (532) at the Cool Fan 1 Relay Connector. Do both fans turn on? | -- | ||
8 |
Does the test lamp illuminate? | -- | ||
9 | Connect a second fused jumper wire between the left fan harness connector terminals. Is the right fan on? | -- | ||
10 |
Does the test lamp illuminate? | -- | ||
11 | Using a second jumper wire, jumper the switch feed circuit (504) and the RH fan feed circuit (409) together at Cool Fan Relay connector. Do the fans come on? | -- | ||
12 |
Is the left fan on? | -- | ||
13 |
Did the test lamp illuminate? | -- | ||
14 | Inspect the PCM connections. Repair faulty connections as necessary. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Cooling Fan Functional Check | |
15 | Repair the Low Speed Fans Control circuit (335) for an open or shorted to battery positive voltage. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Cooling Fan Functional Check | -- |
16 | Inspect the fan motor ground circuit for a open or the fan motor connections. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs or Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Cooling Fan Functional Check | |
17 | Replace the faulty fan motor. Refer to Engine Coolant Fan Motor Replacement in Engine Cooling. Did you complete the replacement? | -- | Go to Cooling Fan Functional Check | -- |
18 | Repair the RH fan feed circuit (409) for an open. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Cooling Fan Functional Check | -- |
19 | Replace the fan which was not operating. Refer to Engine Coolant Fan Motor Replacement in Engine Cooling. Did you complete the replacement? | -- | Go to Cooling Fan Functional Check | -- |
20 | Replace Cool Fan Relay. Did you complete the replacement? | -- | Go to Cooling Fan Functional Check | -- |
21 | Repair the Cool Fan Relay feed circuit (504) for a short to ground. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Cooling Fan Functional Check | |
22 | Repair the open or the grounded circuit for the circuit that did not light. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Cooling Fan Functional Check | -- |
23 | Replace Cool Fan 1 Relay. Did you complete the replacement? | -- | Go to Cooling Fan Functional Check | -- |
24 | Repair the LH fan feed circuit (532) for an open. Refer to Wiring Repairs in Wiring Systems. Did you complete the replacement? | -- | Go to Cooling Fan Functional Check | -- |
25 | Repair the Cool Fan Relay switch feed circuit (504) for an open. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Cooling Fan Functional Check | -- |
26 | Replace Cool Fan Relay . Did you complete the replacement? | -- | Go to Cooling Fan Functional Check | -- |
27 |
Important: : Program the replacement PCM. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Did you complete the replacement? | -- | Go to Cooling Fan Functional Check | -- |
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Cooling Fan Functional Check? | -- | Go to Cooling Fan Functional Check | |
2 |
Did both fans operate with no change? | -- | ||
3 | Did the left fan stop operating? | -- | ||
4 |
Does the test lamp illuminate after several seconds? | -- | ||
5 | Probe the coil feed circuit (1442) at Cool Fan 2 Relay connector using a test lamp that is connected to a known good ground. Does the test lamp illuminate? | -- | ||
6 | Probe the switch feed circuit (1442) at the Cool Fan 2 Relay connector using a test lamp that is connected to a good ground. Does the test lamp illuminate? | -- | ||
7 | Jumper the switch feed circuit (1442) and the RH fan feed circuit (409) together at the Cool Fan 2 Relay connector. Is the right fan on? | -- | ||
8 |
Do the fans switch from low to high speed? | -- | ||
9 |
Does the test lamp illuminate? | -- | ||
10 | Probe the ground circuit (1050) at the Cool Fan Relay connector using a test lamp that is connected to battery positive voltage. Does the test lamp illuminate? | -- | ||
11 | Probe the coil feed circuit (1442) at the Cool Fan Relay connector using a test lamp that is connected to a known good ground. Does the test lamp illuminate? | -- | ||
12 | Repair the High Speed Fans Control circuit (473) for an open between Cool Fan Relay and the splice. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Cooling Fan Functional Check | -- |
13 | Repair the open in the Cool Fan 2 Relay coil feed circuit (1442). Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Cooling Fan Functional Check | -- |
14 | Repair the open in the Cool Fan 2 Relay switch feed circuit (1442). Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Cooling Fan Functional Check | -- |
15 | Replace Cool Fan 2 Relay. Did you complete the replacement? | -- | Go to Cooling Fan Functional Check | -- |
16 | Repair the open in the RH fan feed circuit (409) between Cool Fan 3 Relay and the splice. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Cooling Fan Functional Check | -- |
17 | Repair the High Speed Fans Control circuit (473) for an open or for a short to battery positive voltage. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Cooling Fan Functional Check | -- |
18 | Repair the open in the High Speed Fans Control circuit (473) between Cool Fan Relay and the splice. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Cooling Fan Functional Check | -- |
19 | Repair the open in the ground circuit (1050). Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Cooling Fan Functional Check | -- |
20 | Replace the Cool Fan relay. Did you complete the repair? | -- | Go to Cooling Fan Functional Check | -- |
21 | Repair the open in Cool Fan Relay coil feed circuit (1442). Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Cooling Fan Functional Check | -- |
22 | Inspect the PCM connections. Refer to Testing for Intermittent Conditions and Poor Connections , and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Cooling Fan Functional Check | |
23 |
Important: : Program the replacement PCM. Replace the PCM.Refer to Powertrain Control Module Replacement/Programming . Did you complete the replacement? | -- | Go to Cooling Fan Functional Check | -- |
