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Home >> Chrysler >> 2004 >> Pacifica AWD >> Repair and Diagnosis >> Accessories & Equipment >> Gauges & Instrument Panels >> Body Diagnostic Procedures - HVAC, Ignition Power Accessory, Instrument Cluster, Interior Lighting, Navigation, Overhead Console, Power Door Locks/RKE >> Heating & A/C >> Symptom: *REAR BOOSTER FAN INOPERATIVE >> Diagnostic Procedure

Diagnostic Procedure

*REAR BOOSTER FAN INOPERATIVE - DIAGNOSTIC PROCEDURE

TEST ACTION APPLICABILITY
1 Turn the ignition on.
Press the ATC's PWR switch on.
Press the REAR fan mode switch on, so that it is in manual mode. The word "REAR" should display on the ATC display panel. The word "AUTO" should not be displayed. Turn the Rear Booster Fan Rear Control switch to AUTO for 30 seconds, then slowly turn it from AUTO to high speed and then back to AUTO.
With the DRBIII®, read the active ATC DTCs.
Does the DRBIII® display any DTCs?
  1. Yes: Return to the Heating & A/C SYMPTOM LIST and choose the symptom(s).

    Perform BODY VERIFICATION TEST VER-1 .

  2. No: Go To 2
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2 Turn the ignition on.
With the DRBIII®, read IPM DTCs.
Does the DRBIII® display any DTCs?
  1. Yes: For Integrated Power Module (IPM) DTCs related to the front blower or rear fan relay circuits, refer to the Heating & A/C category. For all other IPM DTCs, refer to appropriate category for the related symptom(s).

    Perform BODY VERIFICATION TEST VER-1 .

  2. No: Go To 3
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3 Turn the ignition off.
Remove and inspect IPM Fuse #34 (Rear Booster Fan Fuse).
Is the fuse open?
  1. Yes: Go To 4
  2. No: Go To 7
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4 Replace IPM Fuse #34 (Rear Booster Fan Fuse).
Turn the ignition on.
Operate the Rear Booster Fan in all speeds.
Start the engine and operate the ATC system in all modes and speeds.
Does the Rear Booster Fan operate properly without blowing the fuse?
  1. Yes: Refer to SYSTEM WIRING DIAGRAMS to help isolate a possible intermittent short to ground condition.

    Perform BODY VERIFICATION TEST VER-1 .

  2. No: Go To 5
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5 Turn the ignition off.
Disconnect the Rear Booster Fan Power Module C1 harness connector.
Measure the resistance between ground and the Fused Rear Booster Fan Relay Output circuit.
Is the resistance below 10K ohms?
  1. Yes: Repair the Fused Rear Booster Fan Relay Output circuit for a short to ground. Replace IPM Fuse #34 (Rear Booster Fan Fuse).

    Perform BODY VERIFICATION TEST VER-1 .

  2. No: Go To 6
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6 Turn the ignition off.
Replace IPM Fuse #34 (Rear Booster Pan Fuse).
Disconnect the Rear Booster Fan Power Module C1 harness connector.
Disconnect the Rear Booster Fan Power Module C2 harness connector.
Connect a jumper wire between the Fused Rear Booster Pan Relay Output circuit in the Rear Booster Fan Power Module C1 harness connector and the Booster Fan Supply circuit in the Rear Booster Fan Power Module C2 harness connector.
Connect a jumper wire between the Ground circuit in the Rear Booster Pan Power Module C1 harness connector and the Booster Fan Ground circuit in the Rear Booster Fan Power Module C2 harness connector.
Turn the ignition on.
Does the Rear Booster Fan operate at full speed without blowing the fuse?
  1. Yes: Replace the Rear Booster Fan Power Module in accordance with the Service Information. Replace IPM Fuse #34 (Rear Booster Pan Fuse).

    Perform BODY VERIFICATION TEST VER-1 .

  2. No: Replace the Rear Booster Fan in accordance with the Service Information. Replace IPM Fuse #34 (Rear Booster Fan Fuse).

    Perform BODY VERIFICATION TEST VER-1 .

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7 Ensure IPM Fuse #34 (Rear Booster Fan Fuse) is installed.
Disconnect the Rear Booster Fan 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 Rear Booster Fan Relay Output circuit in the Rear Booster Fan Power Module C1 harness connector.
Does the test light illuminate brightly?
  1. Yes: Go To 8
  2. No: Go To 14
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8 Turn the ignition off.
Disconnect the Rear Booster Fan Power Module C1 harness connector.
Measure the resistance between ground and the Ground circuit.
Is the resistance below 5.0 ohms?
  1. Yes: Go To 9
  2. 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 Rear Booster Fan Power Module C1 harness connector.
Disconnect the ATC C1 harness connector.
Turn the ignition on.
Measure the voltage of the Rear Booster Fan Control circuit.
Is the voltage above 0.2 volts?
  1. Yes: Repair the Rear Booster Fan Control circuit for a short to voltage.

    Perform BODY VERIFICATION TEST VER-1 .

  2. No: Go To 10
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10 Turn the ignition off.
Disconnect the Rear Booster Fan Power Module C1 harness connector.
Disconnect the ATC C1 harness connector.
Measure the resistance of the Rear Booster Fan Control circuit between the Rear Booster Fan Power Module C1 harness connector and the ATC C1 harness connector.
Is the resistance below 5.0 ohms?
  1. Yes: Go To 11
  2. No: Repair the Rear Booster Fan Control circuit for an open.

    Perform BODY VERIFICATION TEST VER-1 .

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11 Turn the ignition off.
Reconnect the Rear Booster Fan Power Module C1 harness connector.
Reconnect the ATC C1 harness connector.
Start the engine.
Press the ATC's PWR switch on.
Press the REAR fan mode switch on, so that it is in manual mode.
The word "REAR" should display on the ATC display panel.
The word "AUTO" should not be displayed.
Turn the Rear Booster Fan Rear Control switch to the low speed setting.
While back probing, measure the voltage of the Rear Booster Fan Control circuit in the ATC C1 harness connector.
Is the voltage above 7.5 volts?
  1. Yes: Go To 12
  2. No: Replace the Rear Booster Fan Power Module in accordance with the Service Information.

    Perform BODY VERIFICATION TEST VER-1 .

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12 Turn the ignition off.
Reconnect all previously disconnected components.
Connect the DRBIII® X10 Scope Probe CH7061 to the DRBIII®.
Select the following from the DRBIII® menu: PEP Module Tools; Lab Scope; Live Data; and Lab Scope.
Set the time to 10ms/Div.
Set the voltage range to +20.0v.
Set the offset to 4.00v.
Set the Probe to X10.
Start the engine.
Press the ATC's PWR switch on.
Press the REAR fan mode switch on, so that it is in manual mode. The word "REAR" should display on the ATC display panel. The word "AUTO" should not be displayed. Using the X10 Scope Probe, back probe the Rear Booster Fan Control circuit in the ATC C1 harness connector.
NOTE: The RR Booster Fan Power Module provides a 12.0v signal to the ATC over the Rear Booster Fan Control circuit. The ATC provides a variable duty cycle ground to the 12.0v signal based on input from the Rear Booster Fan Rear Control switch.
NOTE: When the fan speed is set to low, the ATC provides a short duty cycle (less time grounding the signal voltage).
NOTE: As higher fan speeds are requested, the ATC increases the duty cycle (more time grounding the signal voltage).
NOTE: When the highest fan speed is requested, the duty cycle increases to where the signal pattern is almost a flat line (with brief voltage spikes).

Set the fan speed to low, then slowly raise the fan speed to high while observing the DRBIII® display.
The voltage on the scope pattern should cycle from approximately 0 volts (duty cycle on) to 12.0 volts (duty cycle off) for all fan speeds.
The duty cycle pattern should change smoothly as the fan speed changes from low to high.
Does the DRBIII® display the voltage range and duty cycle as described above?
  1. Yes: Go To 13
  2. No: Replace the Automatic Temperature Control (ATC) in accordance with the Service Information.

    Perform BODY VERIFICATION TEST VER-1 .

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13 Turn the ignition off.
Disconnect the Rear Booster Fan Power Module C1 harness connector.
Disconnect the Rear Booster Fan Power Module C2 harness connector.
Connect a jumper wire between the Fused Rear Booster Pan Relay Output circuit in the Rear Booster Fan Power Module C1 harness connector and the Booster Fan Supply circuit in the Rear Booster Fan Power Module C2 harness connector.
Connect a jumper wire between the Ground circuit in the Rear Booster Fan Power Module C1 harness connector and the Booster Fan Ground circuit in the Rear Booster Fan Power Module C2 harness connector.
Turn the ignition on.
Does the Rear Booster Fan operate at full speed?
  1. Yes: Replace the Rear Booster Fan Power Module in accordance with the Service Information.

    Perform BODY VERIFICATION TEST VER-1 .

  2. No: Replace the Rear Booster Fan in accordance with the Service Information.

    Perform BODY VERIFICATION TEST VER-1 .

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14 Turn the ignition off.
Remove the Rear Booster Fan Relay from the IPM.
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, probe cavity 30 of the Rear Booster Fan Relay connector.
Does the test light illuminate brightly?
  1. Yes: Go To 15
  2. No: Replace the Integrated Power Module (IPM) in accordance with the Service Information.

    Perform BODY VERIFICATION TEST VER-1 .

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15 Turn the ignition off.
Remove the Rear Booster Fan Relay from the IPM.
Remove IPM Fuse #34 (Rear Booster Fan Fuse).
Measure the resistance between cavity 87 of the Rear Booster Fan Relay connector and IPM Fuse #34 (power input cavity).
Is the resistance below 5.0 ohms?
  1. Yes: Go To 16
  2. No: Replace the Integrated Power Module (IPM) in accordance with the Service Information.

    Perform BODY VERIFICATION TEST VER-1 .

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16 Turn the ignition off.
Make sure that the Rear Booster Fan Relay is installed.
Remove IPM Fuse #34 (Rear Booster Fan Fuse).
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, probe IPM Fuse #34 (power input cavity).
Does the test light illuminate brightly?
  1. Yes: Go To 17
  2. No: Replace the Rear Booster Fan Relay in accordance with the Service Information.

    Perform BODY VERIFICATION TEST VER-1 .

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17 Turn the ignition off.
Remove IPM Fuse #34 (Rear Booster Fan Fuse).
Disconnect the IPM C8 harness connector.
Measure the resistance between IPM Fuse #34 (power output cavity) and cavity 2 of the IPM C8 connector (IPM side).
Is the resistance below 5.0 ohms?
  1. Yes: Repair the Fused Rear Booster Fan Relay Output circuit for an open.

    Perform BODY VERIFICATION TEST VER-1 .

  2. No: Replace the Integrated Power Module (IPM) in accordance with the Service Information.

    Perform BODY VERIFICATION TEST VER-1 .

 All
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