For 1990-2009 cars

Step | Action | Yes | No
--- | --- | --- | ---
The main fan motor is mounted on the left side of the radiator/condenser assembly. The fans run at low speed (series configuration) when the A/C is operating and the engine coolant temperature (ECT) is below 83°C (181°F). The fans run at high speed (parallel configuration) when the ECT is above 93°C (199°F).

A short to ground in the ground circuit of the A/C fan no. 1 and 2 relays will cause both fans to be inoperative once the ECT reaches 93°C (199°F). This table assumes that the auxiliary (right side) fan motor is functioning normally.

The following are symptoms and possible causes.

• | Both fans inoperative:

- | Open in the supply voltage circuit to the fan no. 1 and the engine main relays in fuse and relay block 1

- | High resistance or poor connection in fuse and relay block 1

- | Faulty engine main relay

- | Short to ground in the fan no. 1 or the fan no. 2 coil ground circuit

- | Engine coolant temperature (ECT) sensor or powertrain control module (PCM) malfunction

• | Main fan inoperative:

- | Faulty main fan motor

- | Faulty fan no. 1 relay

- | Open in main fan circuit

• | Auxiliary fan inoperative:

- | Faulty auxiliary fan motor

- | Faulty fan no. 2 relay

- | Open in auxiliary fan circuit

• | Both fans inoperative in low speed:

- | Faulty fan no. 2 relay

- | Faulty fan no. 3 relay

- | Open in series portion of fan circuit

1 | Did you perform the HVAC System Check? | Go to Step 2 | Go to HVAC System Check
2 |

1. Run the engine until operating temperature is reached and the thermostat opens.
2. Stop the engine.
3. Exchange the fan no. 1 relay with a known good relay (the fan no. 3 relay, the A/C MG relay, or the horn relay).
4. Start the engine.

Does the main fan operate?

Go to Step 16

Go to Step 3

3 |

1. Stop the engine.
2. Disconnect the main fan motor connector.
3. Connect a test lamp across the main fan motor connector.
4. Start the engine.

Does the test lamp light?

Go to Step 4

Go to Step 5

4 | Replace the main fan motor. Refer to Engine Cooling Fan Replacement in Engine Cooling. Is the repair complete? | Go to HVAC System Check | --
5 | Test for an open in the WHT/BLK wire between the main fan motor terminal 1 and G103. Is an open present? | Go to Step 18 | Go to Step 6
6 | Test for an open in the BLK/RED wire between the main fan motor terminal 2 and the fan no. 1 relay terminal 23. Refer to

#### Fuse and Relay Block 1

(1) | ST Relay
(2) | HEAD Relay
(3) | EFI or F-HTR Relay
(4) | Fuse Puller
(5) | ENGINE MAIN Relay
(6) | HORN Relay
(7) | AM1 Fuse 50A
(8) | RDI Fuse 30A
(9) | FAN Relay
(10) | ALT-S Fuse 7.5A
(11) | Empty
(12) | Not Used
(13) | HORN Fuse 20A
(14) | Not Used
(15) | Not Used
(16) | AM2 Fuse 30A
(17) | HAZARD Fuse 20A
(18) | DOME Fuse 20A
(19) | ALT Fuse 100A
(20) | ABS Fuse 50A
(21) | MAIN Fuse 50A
(22) | Not Used
(23) | Fuse and Relay Block 1

Is an open present?

Go to Step 7

Go to Step 8

7 |

1. Test for an open in the BLK/RED wire between the main fan motor terminal 2 and connector 3 terminal 1 of fuse and relay block 1.
2. Test for an open between the fan no. 1 relay terminal 23 and connector 3 terminal 1 of fuse and relay block 1.

Is the BLK/RED wire open?

Go to Step 18

Go to Step 15

8 | Test for battery voltage at the fan no. 1 relay terminal 22. Refer to

#### Fuse and Relay Block 1

(1) | ST Relay
(2) | HEAD Relay
(3) | EFI or F-HTR Relay
(4) | Fuse Puller
(5) | ENGINE MAIN Relay
(6) | HORN Relay
(7) | AM1 Fuse 50A
(8) | RDI Fuse 30A
(9) | FAN Relay
(10) | ALT-S Fuse 7.5A
(11) | Empty
(12) | Not Used
(13) | HORN Fuse 20A
(14) | Not Used
(15) | Not Used
(16) | AM2 Fuse 30A
(17) | HAZARD Fuse 20A
(18) | DOME Fuse 20A
(19) | ALT Fuse 100A
(20) | ABS Fuse 50A
(21) | MAIN Fuse 50A
(22) | Not Used
(23) | Fuse and Relay Block 1

in Wiring Systems.

Is battery voltage present?

Go to Step 16

Go to Step 9

9 | Test for an open between terminal 22 of the fan no. 1 relay and terminal 14 of the engine main relay in fuse and relay block 1. Is an open present? | Go to Step 15 | Go to Step 10
10 | Test for battery voltage at terminal 16 of the engine main relay. Is battery voltage present? | Go to Step 12 | Go to Step 11
11 | Test for an open in the BLK/YEL wire between fuse and relay block 1 and fuse and relay block 2 OR in the BLK/YEL wire between fuse and relay block 2 and junction block 2. Refer to Wiring Repairs in Wiring Systems. Is an open present? | Go to Step 18 | Go to Step 15
12 | Test for battery voltage at terminal 13 of the engine main relay. Is battery voltage present? | Go to Step 14 | Go to Step 13
13 | Test for an open in the WHT wire to connector 4 terminal 2 of fuse and relay block 1. Is an open present? | Go to Step 18 | Go to Step 15
14 | Test for an open in the WHT/BLK wire between fuse and relay block 1 and G103. Is an open present? | Go to Step 18 | Go to Step 17
15 | Replace fuse and relay block 1. Refer to Underhood Fuse Block Replacement in Engine Electrical. Is the repair complete? | Go to HVAC System Check | --
16 | Replace the fan no. 1 relay. Refer to Cooling Fan Relay Replacement . Is the repair complete? | Go to HVAC System Check | --
17 | Replace the engine main relay. Refer to Cooling Fan Relay Replacement . Is the repair complete? | Go to HVAC System Check | --
18 | Repair the open. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | Go to HVAC System Check | --