Step | Action | Yes | No |
|---|---|---|---|
1 | Turn ON the ignition, with the engine OFF. Does the heater water auxiliary pump operate? | Go to Step 2 | Go to Step 3 |
2 | Make sure the engine temperature is below 95°C (203°F). Are the auxiliary engine coolant fans and/or the electric cooling fan operating with the engine temperature below 95°C (203°F)? | Go to Step 5 | Go to Step 4 |
3 | The heater water auxiliary pump does not operate. Refer to Water Pump Inoperative - Electric . Does the heater water auxiliary pump operate properly? | Go to Step 31 | -- |
4 |
Does the auxiliary engine coolant fan #1 and auxiliary engine coolant fan #2 operate at low speed? | Go to Step 6 | Go to Step 7 |
5 | The auxiliary engine coolant fans and/or the electric cooling fan run with the engine temperature below 95°C (203°F) Refer to Cooling Fan Always On - Auxiliary . Are the engine cooling fans operating properly? | Go to Step 31 | -- |
6 | Observe the electric cooling fan. Is the electric cooling fan operating at low speed? | Go to Step 9 | Go to Step 8 |
7 | The auxiliary engine coolant fan #1 and auxiliary engine coolant fan #2 do not operate. Refer to Cooling Fan Inoperative - Auxiliary . Are the engine cooling fans operating properly? | Go to Step 31 | -- |
8 | The electric cooling fan does not operate at low speed. Refer to Cooling Fan Inoperative at Low Speed - Electric . Are the engine cooling fans operating properly? | Go to Step 31 | -- |
9 |
Does the water auxiliary pump operate? | Go to Step 10 | Go to Step 11 |
10 |
Does the auxiliary engine coolant fan #1 operate at high speed? | Go to Step 12 | Go to Step 13 |
11 | Water auxiliary pump does not operate. Refer to Auxiliary Water Pump Inoperative . Does the water auxiliary pump operate properly? | Go to Step 31 | -- |
12 | Observe the auxiliary engine coolant fan #2. Does the auxiliary engine coolant fan #2 operate at high speed? | Go to Step 14 | Go to Step 15 |
13 | The auxiliary engine coolant fan #1 does not operate at high speed. Refer to Cooling Fan Inoperative - Auxiliary . Are the engine cooling fans operating properly? | Go to Step 31 | -- |
14 |
Does the electric cooling fan operate at high speed? | Go to Step 16 | Go to Step 17 |
15 | The auxiliary engine coolant fan #2 does not operate at high speed. Refer to Cooling Fan Inoperative - Auxiliary . Are the engine cooling fans operating properly? | Go to Step 31 | -- |
16 |
Does the auxiliary engine coolant fan #1 and auxiliary engine coolant fan #2 run at low speed when the compressor clutch coil is turned ON? | Go to Step 19 | Go to Step 18 |
17 | The electrical cooling fan does not operate at high speed. Refer to Cooling Fan Inoperative . Are the engine cooling fans operating properly? | Go to Step 31 | -- |
18 | The auxiliary engine coolant fan #1 and auxiliary engine coolant fan #2 do not operate when the compressor is turned ON. Refer to Cooling Fan Inoperative - Auxiliary . Are the engine cooling fans operating properly? | Go to Step 31 | -- |
19 |
Does the auxiliary engine coolant fan #1 and auxiliary engine coolant fan #2 operate at low speed? | Go to Step 20 | Go to Step 21 |
20 | Continue to allow the engine to run until the secondary cooling fan temperature switch reaches 105°C (221°F). The secondary cooling fan temperature switch should close and energize the fan control relay K28 and fan control relay K52. Does the auxiliary engine coolant fan #1 and auxiliary engine coolant fan #2 operate at high speed? | Go to Step 24 | Go to Step 25 |
21 | Test the control circuit of the fan control relay K26 for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 31 | Go to Step 22 |
22 | Test the ground circuit of the primary cooling fan temperature switch for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 31 | Go to Step 23 |
23 | Replace the primary cooling fan temperature switch. Refer to Engine Cooling Fan Control Switch Replacement . Did you complete the repair? | Go to Step 31 | -- |
24 | Continue to allow the engine to run until the primary cooling fan temperature switch reaches 110°C (230°F). The stage 2 contacts should close and energize the fan control relay K67. Does the electric cooling fan operate at high speed? | Go to Step 29 | Go to Step 27 |
25 | Test the control circuit of the fan control relay K28 and fan control relay K52 for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 31 | Go to Step 26 |
26 | Replace the secondary cooling fan temperature switch. Did you complete the repair? | Go to Step 31 | -- |
27 | Test the fan control relay K67 control circuit of the relay coil for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 31 | Go to Step 28 |
28 | Replace the primary cooling fan temperature switch. Refer to Engine Cooling Fan Control Switch Replacement . Did you complete the repair? | Go to Step 31 | -- |
29 |
Does the auxiliary engine coolant fan #1 and auxiliary engine coolant fan #2 operate at high speed? | Go to Step 31 | Go to Step 30 |
30 | The auxiliary engine coolant fan #1 and auxiliary engine coolant fan #2 do not operate at high speed when the A/C refrigerant pressure switch reaches 275 psi. Refer to Cooling Fan Inoperative - Auxiliary . Are the engine cooling fans operating properly? | Go to Step 31 | -- |
31 | Confirm that the engine cooling fans and auxiliary water pumps operate properly . Refer to Cooling System Description . Do the engine cooling fans and auxiliary water pumps operate properly? | System OK | Go to Step 1 |
