Step
| Action
| Value(s)
| Yes
| No
|
1
| Did you perform the Coolant Fan Diagnostic System Check?
| --
|
Go to Step 2
| Refer to
Cooling Fan System Check
.
|
2
|
- Turn on the ignition.
- Locate the coolant fan test connector within the ECM housing.
- Use a fused jumper to connect terminal 1 of the coolant
fan test connector to a known good ground.
Does the ECM cooling blower turn ON?
| --
|
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 these circuits
are OK. Refer to
Engine Cooling Fan Control Switch Replacement
in Engine Cooling.
Did you complete the repair?
| --
|
Go to Step
15
| --
|
4
|
- Disconnect the ECM relay K48.
- Use the DMM in order to measure the voltage between terminal 2
of the ECM relay K48 and a known good ground.
Does the voltage measure near the specified value?
| B+
|
Go to Step 6
|
Go to Step
5
|
5
|
- Locate an open or a high resistance in CKT A60.
- Repair the open or the high resistance in CKT A60.
Did you complete the repair?
| --
|
Go to Step
15
| --
|
6
| Use the DMM in order to measure the voltage between terminal 4
of the ECM relay K48 and a known good ground.
Does the voltage measure near the specified value?
| B+
|
Go to Step 8
|
Go to Step 7
|
7
|
- Locate an open or a high resistance in CKT X235.
- Repair the open or the high resistance in CKT X235.
Did you complete the repair?
| --
|
Go to Step 15
| --
|
8
| Connect a fused jumper between terminal 4 and terminal 8
of the ECM relay K48.
Does the ECM cooling blower turn ON?
| --
|
Go to Step 9
|
Go to Step 10
|
9
| Replace the ECM relay K48.
Did you complete the repair?
| --
|
Go to Step
15
| --
|
10
|
- Disconnect the ECM cooling blower connector.
- Use the DMM in order to measure the voltage between terminal 1
of the ECM cooling blower connector and a known good ground.
Does the voltage measure near the specified value?
| B+
|
Go to Step 12
|
Go to Step
11
|
11
|
- Locate an open or a high resistance in CKT FM235.
- Repair the open or the high resistance in CKT FM235.
Did you complete the repair?
| --
|
Go to Step
15
| --
|
12
| Use the DMM in order to measure the resistance between terminal 2
of the ECM cooling blower connector and a known good ground.
Does the resistance measure near the specified value?
| Less than 5 ohms
|
Go to Step 14
|
Go to Step 13
|
13
|
- Locate an open or a high resistance in CKT F59.
- Repair the open or the high resistance in CKT F59.
Did you complete the repair?
| --
|
Go to Step
15
| --
|
14
| Replace the ECM cooling blower. Refer to
Cooling Fan and Duct Replacement
in Engine Cooling.
Did you complete the repair?
| --
|
Go to Step
15
| --
|
15
|
- Connect all connectors and components that were previously disconnected.
- Verify that the ECM cooling blower operates properly.
Does the ECM cooling blower operate properly?
| --
| Refer to
Cooling Fan System Check
.
|
Go to Step
1
|
