Diagnostic Procedure
WARNING: This page is about a different car, the 2005 Dodge Stratus and 2005 Chrysler Sebring. However, it is still accessible from the selected car via links, so may be relevant.
DIAGNOSTIC PROCEDURE - BLOWER MOTOR INOPERATIVE - ATC
| TEST | ACTION | APPLICABILITY |
|---|---|---|
| 1 | Turn the ignition off. Remove and inspect JB Fuse #1. Is the fuse open? Yes --> Go To 2 No --> Go To 7 |
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| 2 | Replace JB Fuse #1. Turn the ignition on. Operate the blower motor in all speeds. Start the engine and operate the ATC system in all modes and speeds. Does the blower motor operate properly without blowing the fuse? Yes --> Refer to appropriate SYSTEM WIRING DIAGRAMS article to help isolate a possible intermittent short to ground condition. Perform BODY VERIFICATION TEST - VER 1 . No --> Go To 3 |
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| 3 | Turn the ignition off. Disconnect the Blower Power Module C1 harness connector. Measure the resistance between ground and the Fused Ignition Switch Output circuit. Is the resistance below 10K ohms? Yes --> Repair the Fused Ignition Switch Output circuit for a short to ground. Replace JB Fuse #1. Perform BODY VERIFICATION TEST - VER 1 . No --> Go To 4 |
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| 4 | Turn the ignition off. Disconnect the Blower Power Module C2 harness connector. Disconnect the Blower Motor harness connector. Measure the resistance between the Blower Motor Supply circuit and the Blower Motor Ground circuit. Is the resistance below 10K ohms? Yes --> Repair the Blower Motor Supply circuit for a short to the Blower Motor Ground circuit. Replace JB Fuse #1. Perform BODY VERIFICATION TEST - VER 1 . No --> Go To 5 |
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| 5 | Turn the ignition off. Disconnect the Blower Power Module C2 harness connector. Disconnect the Blower Motor harness connector. Measure the resistance between ground and the Blower Motor Supply circuit. Is the resistance below 10K ohms? Yes --> Repair the Blower Motor Supply circuit for a short to ground. Replace JB Fuse #1. Perform BODY VERIFICATION TEST - VER 1 . No --> Go To 6 |
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| 6 | Turn the ignition off. Replace JB Fuse #1. Reconnect the Blower Motor harness connector. Disconnect the Blower Power Module C1 harness connector. Disconnect the Blower Power Module C2 harness connector. Connect a jumper wire between the Fused Ignition Switch Output circuit in the Blower Power Module C1 harness connector and the Blower Motor Supply circuit in the Blower Power Module C2 harness connector. Connect a jumper wire between the Ground circuit in the Blower Power Module C1 harness connector and the Blower Motor Ground circuit in the Blower Power Module C2 harness connector. Turn the ignition on. Does the Blower Motor operate at Hi speed without blowing the fuse? Yes --> Replace the Blower Power Module in accordance with the Service Information. Perform BODY VERIFICATION TEST - VER 1 . No --> Replace the Blower Motor in accordance with the Service Information. Replace JB Fuse #1. Perform BODY VERIFICATION TEST - VER 1 . |
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| 7 | Ensure JB Fuse #1 is installed. Disconnect the Blower Power Module C1 harness connector. Turn the ignition on.
NOTE:
The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery. Using a 12-volt test light connected to ground, back probe the Fused Ignition Switch Output circuit in the Blower Power Module C1 harness connector. Does the test light illuminate brightly? Yes --> Go To 8 No --> Repair the Fused Ignition Switch Output circuit for an open. Perform BODY VERIFICATION TEST - VER 1 . |
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| 8 | Turn the ignition off. Disconnect the Blower Power Module C1 harness connector. Measure the resistance between ground and the Ground circuit. Is the resistance below 5.0 ohms? Yes --> Go To 9 No --> Repair the Ground circuit for an open. Perform BODY VERIFICATION TEST - VER 1 . |
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| 9 | Turn the ignition off. Disconnect the Blower Power Module C1 harness connector. Disconnect the Body Control Module C1 harness connector. Turn the ignition on. Measure the voltage between the Blower Motor Control circuit and ground. Is the voltage above 0.2 volts? Yes --> Repair the Blower Motor Control circuit for a short to voltage. Perform BODY VERIFICATION TEST - VER 1 . No --> Go To 10 |
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| 10 | Turn the ignition off. Disconnect the Blower Power Module C1 harness connector. Disconnect the Body Control Module C1 harness connector. Measure the resistance of the Blower Motor Control circuit between the Blower Power Module C1 harness connector and the Body Control Module C1 harness connector. Is the resistance below 5.0 ohms? Yes --> Go To 11 No --> Repair the Blower Motor Control circuit for an open. Perform BODY VERIFICATION TEST - VER 1 . |
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| 11 | Turn the ignition off. Disconnect the Blower Power Module C2 harness connector. Disconnect the Blower Motor harness connector. Measure the resistance of the Blower Motor Supply circuit between the Blower Motor harness connector and the Blower Power Module C2 harness connector. Is the resistance below 5.0 ohms? Yes --> Go To 12 No --> Repair the Blower Motor Supply circuit for an open. Perform BODY VERIFICATION TEST - VER 1 . |
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| 12 | Turn the ignition off. Disconnect the Blower Power Module C2 harness connector. Disconnect the Blower Motor harness connector. Measure the resistance of the Blower Motor Ground circuit between the Blower Motor harness connector and the Blower Power Module C2 harness connector. Is the resistance below 5.0 ohms? Yes --> Go To 13 No --> Repair the Blower Motor Ground circuit for an open. Perform BODY VERIFICATION TEST - VER 1 . |
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| 13 | Turn the ignition off. Reconnect the Blower Motor harness connector. Reconnect the Blower Power Module C1 and C2 harness connectors. Back probe one voltmeter lead to the Blower Motor Control ckt in the Body Control Module C1 harness connector and the other lead to ground. Reconnect the Body Control Module C1 harness connector. Start the engine. Turn the Automatic Temperature Control off. Observe the voltmeter. Is the voltage above 11.0 volts? Yes --> Go To 14 No --> Replace the Blower Power Module in accordance with the Service Information. Perform BODY VERIFICATION TEST - VER 1 . |
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| 14 | Turn the ignition off. Reconnect all previously disconnected components. Connect the DRBIII® Scope Input Cable CH7058, Cable-To-Probe Adapter CH7062, and the Red (+) and Black (-) X1 Test Leads CH7030 to the DRBIII®. Select the following from the DRBIII® menu: PEP Module Tools; Lab Scope; Live Data; and Lab Scope. Set the time to 0.4ms/Div. Set the voltage range to +20.0v. Set the Offset to 4.00v. Set the Probe to X1. Start the engine. Turn Automatic Temperature Control on. Using the Red (+) X1 Test Lead, back probe the Blower Motor Control circuit in the Blower Power Module C1 harness connector. Connect the Black (-) X1 Test Lead to ground.
NOTE:
Over the Blower Motor Control circuit, the Blower Power Module provides a battery supply voltage signal to the Body Control Module (BCM) while the BCM provides a variable duty cycle ground based on input from the blower control switch.
NOTE:
When the blower control switch is set to Lo speed, the BCM provides a short duty cycle (less time grounding the signal). As higher blower speeds are requested, the BCM increases the duty cycle (more time grounding the signal).
NOTE:
When the blower control switch is set to High speed, the duty cycle increases to where the signal pattern is a flat line on ground. Set the blower control to LO speed and then slowly turn it to HI speed while observing the DRBIII® display. The duty cycle pattern should change smoothly as the blower switch is turned from Lo to High. The high part of the cycle will decrease as the blower speed increases. Does the DRBIII® display the signal as described above? Yes --> Go To 15 No --> Replace and program the Body Control Module in accordance with the Service Information. Perform BODY VERIFICATION TEST - VER 1 . |
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| 15 | Turn the ignition off. Disconnect the Blower Power Module C1 harness connector. Disconnect the Blower Power Module C2 harness connector. Connect a jumper wire between the Fused Ignition Switch Output circuit in the Blower Power Module C1 harness connector and the Blower Motor Supply circuit in the Blower Power Module C2 harness connector. Connect a jumper wire between the Ground circuit in the Blower Power Module C1 harness connector and the Blower Motor Ground circuit in the Blower Power Module C2 harness connector. Turn the ignition on. Does the Blower Motor operate at full speed? Yes --> Replace the Blower Power Module in accordance with the Service Information. Perform BODY VERIFICATION TEST - VER 1 . No --> Replace the Blower Motor in accordance with the Service Information. Perform BODY VERIFICATION TEST - VER 1 . |
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