Table 1: | Reference Table |
Symptom | Causes | ||||||||||
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Main fan always ON |
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Auxiliary fan always ON |
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Both fans always ON |
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Step | Action | Yes | No |
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Schematic Reference: Engine Cooling Schematics | |||
The main fan motor is mounted on the left side of the radiator/condenser assembly. The auxiliary fan motor is mounted on the right side of the radiator/condenser assembly. The fans run at low speed in 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 in parallel configuration when the ECT is above 93°C (199°F). An open in the ground circuit of the A/C fan 1 and 2 relays will cause both fans to operate at high speed when the ECT is below 93°C (199°F). This table assumes that the main fan motor and/or the auxiliary fan motor runs continuously with the ignition switch in the RUN position and the ECT below 93°C (199°F). | |||
1 | Did you review the Cooling System Description and Operation and perform the necessary inspections? | Go to Step 2 | |
2 |
Is only the main fan motor running continuously? | Go to Step 5 | Go to Step 3 |
3 | Is only the auxiliary fan motor running continuously? | Go to Step 9 | Go to Step 4 |
4 | Are both fan motors running continuously? | Go to Step 12 | Go to Step 1 |
5 | Remove the fan 1 relay from fuse and relay block 1. Does the main fan motor run? | Go to Step 6 | Go to Step 7 |
6 | Repair the short to voltage in the main fan motor supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 18 | -- |
7 | Test the fan 1 relay control circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 18 | Go to Step 8 |
8 | Replace the fan 1 relay. Refer to Cooling Fan Relay Replacement . Did you complete the replacement? | Go to Step 18 | -- |
9 | Remove the fan 2 relay from fuse and relay block 2. Does the auxiliary fan motor run? | Go to Step 10 | Go to Step 11 |
10 | Repair the short to ground in the circuit between the auxiliary fan motor and fuse and relay block 2. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 18 | -- |
11 | Replace the fan 2 relay. Refer to Cooling Fan Relay Replacement . Did you complete the replacement? | Go to Step 18 | -- |
12 | Remove the fan 3 relay from fuse and relay block 2. Do both fan motors run? | Go to Step 13 | Go to Step 15 |
13 | Test the fan 2 relay control circuit, including the A/C refrigerant pressure switch, for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 18 | Go to Step 14 |
14 |
Did you find and correct the condition? | Go to Step 18 | -- |
15 |
Does continuity exist in either relay? | Go to Step 16 | Go to Step 17 |
16 | Replace the faulty relay. Refer to Cooling Fan Relay Replacement . Did you complete the replacement? | Go to Step 18 | -- |
17 | Repair the short to voltage in the fan 3 relay coil supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 18 | -- |
18 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 3 |