| 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
RH and LH Cooling Fans
.
Circuit Description
Power for the fan motors is supplied through the U/H Electrical Center. The cooling fan relays are energized when current flows from the Cool Fan #1 Fuse in the U/H Electrical Center (U/H BEC) and Cool Fan #2 fuse in the U/H Electrical Center (U/H BEC) through the relay coils to ground through the PCM. The #1 Fan control Relay circuit is grounded for low speed fans operation. The #1 Fan Control Relay control circuit and the Mode control relay (cool fan series) and #2 Fan Control Relay circuits are all grounded for high speed fans operation.
During low speed fans operation the PCM supplies a ground path for the #1 Fan Control Relay. This closes the #1 Fan Control relay contacts, allowing current to flow from the U/H Electrical Center through the relay contacts to the left hand cooling fan motor. During low speed operation, the ground path for the left hand cooling fan motor is through the #2 Fan Control Relay and the right hand engine cooling fan motor. 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 #1 Fan control Relay. The PCM also supplies a ground path for #2 Fan Control Relay and the Mode control relay (cool fan series). This closes all three cooling fan relays. During high speed fans operation, both the right and the left hand engine cooling fans are supplied current from the Underhood Bussed Electrical Center (U/H ELECTRICAL CENTER) and each cooling fan has its own ground path.
Diagnostic Aids
Check for the following conditions:
| • | Poor connection at the PCM, cooling fan relays, or cooling fan motors. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection. |
| • | Damaged harness. Inspect the wiring harness for damage. Refer to Intermittents and Poor Connections Diagnosis , Connector Repairs , and Wiring Repairs . |
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 | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (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 VDOT Air Conditioning (A/C) System Diagnosis for further diagnosis of the A/C system | |
9 | Does the scan tool display A/C request as YES? | -- | Go to VDOT Air Conditioning (A/C) System Diagnosis for further diagnosis of the A/C Refrigerant Pressure Sensor | Go to VDOT Air Conditioning (A/C) System Diagnosis for further diagnosis of the A/C system |
10 |
Important: : Program the replacement PCM. Refer to Powertrain Control Module Replacement/Programming . Replace the PCM.Is the action complete? | -- | System OK | -- |
Step | Action | Value(s) | 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 3 Relay. Are both fans off? | -- | ||
4 |
Does the J 35616-200 test lamp illuminate? | -- | ||
5 | Probe terminal A of the right fan connector using a J 35616-200 test lamp that is connected to a known good ground. Does the J 35616-200 test lamp illuminate? | -- | ||
6 | Probe the High Speed Fans control
circuit (473) at the Cool Fan 3 Relay connector in the
Does the J 35616-200 test lamp illuminate? | -- | ||
7 |
Is the J 35616-200 test lamp still illuminated? | -- | ||
8 | Probe the Low Speed Fans Control circuit (335) at the Cool Fan 1 Relay connector using the J 35616-200 test lamp that is connected to battery positive voltage. Does the J 35616-200 test lamp illuminate? | -- | ||
9 |
Is the J 35616-200 test lamp still illuminated? | -- | ||
10 | Repair the LH fan feed circuit (504) for a short to voltage. Refer to Wiring Repairs . Did you find and correct the condition? | -- | Go to Cooling Fan Functional Check | |
11 | Repair the RH fan feed circuit (409) for a short to voltage. Refer to Wiring Repairs . Is the action complete? | -- | Go to Cooling Fan Functional Check | -- |
12 | Repair the short to voltage in the Cool Fan 2 Relay feed circuit (532). Refer to Wiring Repairs . Is the action complete? | -- | Go to Cooling Fan Functional Check | -- |
13 | Replace the Cool Fan 1 Relay. Is the action complete? | -- | 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 . Is the action complete? | -- | Go to Cooling Fan Functional Check | -- |
15 | Replace the Cool Fan 2 Relay. Is the action complete? | -- | Go to Cooling Fan Functional Check | -- |
16 |
Important:: Program the replacement PCM. Refer to Powertrain Control Module Replacement/Programming . Replace the PCM. Is the action complete? | -- | Go to Cooling Fan Functional Check | -- |
Step | Action | Values | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Cooling Fan Functional Check? | -- | Go to Electric Cooling Fan Functional Check | |||||||
2 | Did either fan turn ON when the Low Speed Fans were commanded ON? | -- | ||||||||
3 |
Did the Left fan turn OFF? | -- | ||||||||
4 |
Does the test lamp illuminate? | -- | ||||||||
5 | Probe both feed circuits (1640 and 402) at the relay #1 connector locations (B3 and C3) using a test lamp that is connected to a good ground. Does test lamp illuminate for both circuits? | -- | ||||||||
6 |
Important: Leave jumper in place for remainder of this table. Connect a fused jumper wire between the switch feed circuit (402) and the LH fan feed circuit (409) at the relay #1 connector locations (B3 and C1). Do both fans turn ON? | -- | ||||||||
7 |
Does the test lamp illuminate? | -- | ||||||||
8 | Connect a second fused jumper wire between the fan harness connector terminals. Is the right fan ON? | -- | ||||||||
9 |
Does the test lamp illuminate? | -- | ||||||||
10 | Using the second jumper wire, jumper the switch ignition feed circuit (532) and the RH fan feed circuit (504) together at relay #3 connector locations (B9 and C8). Do the fans come ON? | -- | ||||||||
11 |
Is the left fan ON? | -- | ||||||||
12 |
Is the test lamp illuminated? | -- | ||||||||
13 | Inspect the PCM connections. Repair faulty connections as necessary. Refer to Intermittents and Poor Connections Diagnosis and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Electric Cooling Fan Functional Check | |||||||
14 | Repair the relay 1 control circuit (335) for an open or shorted to B+. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Electric Cooling Fan Functional Check | -- | ||||||
15 | Inspect the fan motor ground circuit for a open or the fan motor connections and repair as necessary. Refer to Intermittents and Poor Connections Diagnosis and Connector Repairs or Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Electric Cooling Fan Functional Check | |||||||
16 | Replace the fan motor. Did you complete the repair? | -- | Go to Electric Cooling Fan Functional Check | -- | ||||||
17 | Repair the RH fan feed circuit (504) for an open. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Electric Cooling Fan Functional Check | -- | ||||||
18 | Replace the fan which was not operating. Did you complete the repair? | -- | Go to Electric Cooling Fan Functional Check | -- | ||||||
19 | Replace fan relay #2. Did you complete the repair? | -- | Go to Electric Cooling Fan Functional Check | -- | ||||||
20 | Repair the relay #3 switch feed circuit (532) for a short to ground. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Electric Cooling Fan Functional Check | |||||||
21 |
Did you complete the repair? | -- | Go to Electric Cooling Fan Functional Check | -- | ||||||
22 | Replace fan relay #1. Did you complete the repair? | -- | Go to Electric Cooling Fan Functional Check | -- | ||||||
23 | Repair the LH fan feed circuit (409) for a open. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Electric Cooling Fan Functional Check | -- | ||||||
24 | Repair the relay #3 switch feed circuit (532) for a open. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Electric Cooling Fan Functional Check | -- | ||||||
25 | Replace fan relay #3. Did you complete the repair? | -- | Go to Electric Cooling Fan Functional Check | -- | ||||||
26 |
Important: The replacement PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming . Replace the PCM. Did you complete the repair? | -- | Go to Electric Cooling Fan Functional Check | -- |
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Cooling Fan Functional Check? | -- | Go to Electric 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 (1640) at relay #2 connector location (C6) using a test lamp that is connected to a good ground. Does the test lamp illuminate? | -- | ||
6 | Probe the switch feed circuit (402) at the relay #2 connector location (C4) using a test lamp that is connected to a good ground. Does the test lamp illuminate? | -- | ||
7 | Jumper the switch ignition feed circuit (402) and the RH fan feed circuit (504) together at the relay #2 connector locations (C4 and B6). 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 (150) at the relay #3 connector location (B10) using a test lamp that is connected to B+. Does the test lamp illuminate? | -- | ||
11 | Probe the coil feed circuit (1640) at the relay #3 connector location (B8) using a test lamp that is connected to a good ground. Does the test lamp illuminate? | -- | ||
12 | Repair the relay 2 and 3 control circuit (473) for an open between fan relay #2 and the splice. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Electric Cooling Fan Functional Check | -- |
13 | Repair the open in the relay #2 coil feed circuit (1640). Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Electric Cooling Fan Functional Check | -- |
14 | Repair the open in the relay #2 switch feed circuit (402). Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Electric Cooling Fan Functional Check | -- |
15 | Replace the fan relay #2. Did you complete the repair? | -- | Go to Electric Cooling Fan Functional Check | -- |
16 | Repair the open in the RH fan feed circuit (504) between fan relay #2 and the splice. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Electric Cooling Fan Functional Check | -- |
17 | Repair the fan 2 and 3 relay control circuit (473) for an open or for a short to B+. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Electric Cooling Fan Functional Check | -- |
18 | Repair the open in the fan 2 and 3 relay control circuit (473) between fan relay #3 and the splice. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Electric Cooling Fan Functional Check | -- |
19 | Repair the open in the ground circuit (150). Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Electric Cooling Fan Functional Check | -- |
20 | Replace the fan relay #3. Did you complete the repair? | -- | Go to Electric Cooling Fan Functional Check | -- |
21 | Repair the open in relay #3 coil feed circuit (1640). Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Electric Cooling Fan Functional Check | -- |
22 |
Did you find and correct the condition? | -- | Go to Electric Cooling Fan Functional Check | |
23 |
Important:: The replacement PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming . Replace the PCM. Did you complete the repair? | -- | Go to Electric Cooling Fan Functional Check | -- |
