Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Engine Cooling Schematics DEFINITION: The cooling fan only is inoperative in high speed, low speed or both speeds. | |||
1 | Did you perform the Engine Cooling Diagnostic System Check? | Go to Step 2 | |
2 |
Does the low speed cooling fan turn ON approximately 100°C (212°F) and the high speed fan turn ON approximately 110°C (230°F)? | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 3 |
3 | Are both cooling fan speeds inoperative? | Go to Step 13 | Go to Step 4 |
4 | Is the low speed cooling fan inoperative? | Go to Step 10 | Go to Step 5 |
5 | With the ignition ON and the engine OFF, install a 10 amp fused jumper wire between pin 4 and pin 6 of the coolant fan test connector. Does the cooling fan operate at high speed? | Go to Step 6 | Go to Step 7 |
6 |
Does the cooling fan operate at high speed? | Go to Step 22 | Go to Step 15 |
7 |
Does the test lamp illuminate? | Go to Step 8 | Go to Step 16 |
8 | With a test lamp that is connected to a good ground, probe circuit A710 of the K67 relay. Does the test lamp illuminate? | Go to Step 9 | Go to Step 17 |
9 |
Does the cooling fan operate at high speed? | Go to Step 24 | Go to Step 18 |
10 |
Does the test lamp illuminate? | Go to Step 11 | Go to Step 19 |
11 |
Does the cooling fan operate at low speed? | Go to Step 26 | Go to Step 12 |
12 | Inspect circuit AP1, AP2 or AM16 of the K26 relay for an open or high resistance. Refer to Testing for Continuity in Wiring Systems. Did you find and correct the condition? | Go to Step 32 | Go to Step 28 |
13 |
Does the test lamp illuminate? | Go to Step 14 | Go to Step 20 |
14 | Install a test lamp between circuit AM17 and F100 of the of the cooling fan test connector. Does the test lamp illuminate? | Go to Step 30 | Go to Step 21 |
15 | Repair circuit XM5 of the primary cooling fan switch for an open or high resistance. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 32 | -- |
16 | Repair circuit X2 of the K67 relay for an open, high resistance or short to ground. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 32 | -- |
17 | Repair circuit A710 of the K67 relay for an open, high resistance or short to ground. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 32 | -- |
18 | Repair circuit AM16 of the K67 relay for an open or high resistance. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 32 | -- |
19 | Repair circuit A223 of the K26 relay for an open or high resistance. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 32 | -- |
20 | Repair circuit AM6, AM16 or AM17 of the K67 relay for a short to ground. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 32 | -- |
21 | Repair circuit F100 of the cooling fan for an open or high resistance. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 32 | -- |
22 | Inspect for poor connections at the primary cooling fan temperature switch. Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find the problem? | Go to Step 32 | 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 32 | -- |
24 | Inspect for poor connections at the K67 relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find the problem? | Go to Step 32 | Go to Step 25 |
25 |
Notice: Installation of the proper relay is critical. If an enhanced relay -- equipped with a diode -- is installed into a position requiring a standard relay -- equipped without a diode -- excessive current will damage any components associated with the relay or its associated circuits. Replace the fan control relay K67. Did you complete the repair? | Go to Step 32 | -- |
26 | Inspect for poor connections at the K26 relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find the problem? | Go to Step 32 | Go to Step 27 |
27 |
Notice: Installation of the proper relay is critical. If an enhanced relay -- equipped with a diode -- is installed into a position requiring a standard relay -- equipped without a diode -- excessive current will damage any components associated with the relay or its associated circuits. Replace the fan control relay K26. Did you complete the repair? | Go to Step 32 | -- |
28 | Inspect for poor connections at the engine cooling fan resistor. Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find the problem? | Go to Step 32 | Go to Step 29 |
29 | Replace the engine cooling fan resistor. Refer to Low Speed Cooling Fan Resistor Replacement Did you complete the repair? | Go to Step 32 | -- |
30 | Inspect for poor connections at the cooling fan. Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find the problem? | Go to Step 32 | Go to Step 31 |
31 | Replace the cooling fan. Refer to Engine Cooling Fan Replacement . Did you complete the repair? | Go to Step 32 | -- |
32 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 2 |
