Step
| Action
| Value(s)
| Yes
| No
|
1
| Did you perform the Cooling Fan Diagnostic System Check?
| --
|
Go to Step 2
| Refer to
Cooling Fan System Check
.
|
2
|
- Locate the coolant fan test connector within the ECM housing.
- Use a fused jumper in order to connect terminal 1 of the
coolant fan test connector to a known good ground.
Does the electric cooling fan turn ON at low speed?
| --
|
Go to Step 3
|
Go to Step
4
|
3
|
- Locate an open or a high resistance in circuits XP30 and/or
F600.
- Repair the open or the high resistance in circuits XP30
and/or F600.
- Replace the primary cooling fan temperature switch if circuits XP30
and F600 are OK. Refer to
Engine Cooling Fan Control Switch Replacement
in Engine Cooling.
Did you complete the repair?
| --
|
Go to Step
19
| --
|
4
|
- Disconnect the fan control relay K26 connector.
- Use the DMM to measure the resistance between terminal 1
of the coolant fan test connector and terminal 6 of the fan control
relay K26.
Is the measured resistance within the specified value?
| Less than 5 ohms
|
Go to Step 6
|
Go to Step 5
|
5
|
- Locate an open or a high resistance in circuits XP999 and/or
XP3.
- Repair the open or the high resistance in circuits XP999
and/or XP3.
Did you complete the repair?
| --
|
Go to Step
19
| --
|
6
| Use the DMM in order to measure the voltage between terminal 3
of the fan control relay K26 and a known good ground.
Does the voltage measure near the specified value?
| B+
|
Go to Step 8
|
Go to Step
7
|
7
|
- Inspect fuse #50 for an open.
- Locate an open or high resistance in circuits A6 and/or
A310.
- Repair the open or the high resistance in circuits A6 and/or
A310.
Did you complete the repair?
| --
|
Go to Step
19
| --
|
8
| Use the DMM in order to measure the voltage between terminal 4
of the fan control relay K26 and a known good ground.
Does the voltage measure near the specified value?
| B+
|
Go to Step 10
|
Go to Step
9
|
9
|
- Inspect fuse #52 for an open.
- Locate an open or a high resistance in circuits A300,
A220 and/or A223 if the fuse in OK.
- Repair the open or the high resistance in circuits A300,
A220 and/or A223.
Did you complete the repair?
| --
|
Go to Step 19
| --
|
10
| Connect a fused jumper between terminal 4 and terminal 5
of the fan control relay K26 connector.
Does the engine coolant fan turn ON at half speed?
| --
|
Go to Step 11
|
Go to Step
12
|
11
| Replace the fan control relay K26.
Did you complete the repair?
| --
|
Go to Step
19
| --
|
12
|
- Disconnect the engine coolant fan resistor connector.
- Use the DMM in order to measure the voltage between terminal 1
of the engine coolant fan resistor connector and a known good ground.
Does the voltage measure near the specified value?
| B+
|
Go to Step 14
|
Go to Step 13
|
13
|
- Locate an open, high resistance or a short to ground in circuits
AP2 and/or AP1.
- Repair an open, high resistance or a short to ground in circuits
AP2 and/or AP1.
Did you complete the repair?
| --
|
Go to Step
19
| --
|
14
|
- Disconnect the electric cooling fan connector.
- Use the DMM in order to measure the resistance between terminal 1
of the engine coolant fan resistor connector and terminal A of the
electric cooling fan connector.
Does the resistance measure near the specified value?
| Less than 5 ohms
|
Go to Step 16
|
Go to Step 15
|
15
|
- Locate an open or a high resistance in circuits AM17 and/or
AM6.
- Repair the open or the high resistance in circuits AM17
and/or AM6.
Did you complete the repair?
| --
|
Go to Step
19
| --
|
16
| Use the DMM in order to measure the resistance between terminal B
of the electric cooling fan connector and a known good ground.
Does the resistance measure near the specified value?
| Less than 5 ohms
|
Go to Step 18
|
Go to Step 17
|
17
|
- Locate an open or a high resistance in CKT F100.
- Repair the open or the high resistance in CKT F100.
Did you complete the repair?
| --
|
Go to Step
19
| --
|
18
|
- Check the integrity of the engine coolant fan resistor.
- Replace the engine coolant fan resistor if it is open.
- Replace the electric cooling fan if the engine coolant fan resistor
is OK. Refer to
Engine Cooling Fan Replacement
in Engine Cooling.
Did you complete the repair?
| --
|
Go to Step
19
| --
|
19
|
- Connect all connectors and components that were previously disconnected.
- Verify that the electric cooling fan operates properly at low
speed.
Does the electric cooling fan operate properly at low speed?
| --
| Refer to
Cooling Fan System Check
.
|
Go to Step 1
|
