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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 FAN POT OPEN (ACTIVE) >> Diagnostic Procedure

Diagnostic Procedure

REAR FAN POT OPEN (ACTIVE) - DIAGNOSTIC PROCEDURE

TEST ACTION APPLICABILITY
1 Turn the ignition off.
Disconnect the Rear Booster Fan Rear Control Switch harness connector.
Turn the ignition on.
Measure the voltage of the Rear Fan Sense Supply circuit.
Is the voltage above 5.3 volts?
  1. Yes: Go To 2
  2. No: Go To 3
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2 Turn the ignition off.
Disconnect the ATC C1 harness connector.
Disconnect the Rear Booster Fan Rear Control Switch harness connector.
Turn the ignition on.
Measure the voltage between the Rear Fan Sense Supply circuit and ground.
Is the voltage above 0.2 volts?
  1. Yes: Repair the Rear Fan Sense Supply circuit for a short to voltage.

    Perform BODY VERIFICATION TEST VER-1 .

  2. No: Replace the Automatic Temperature Control (ATC) in accordance with the Service Information.

    Perform BODY VERIFICATION TEST VER-1 .

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3 Turn the ignition off.
Disconnect the Rear Booster Fan Rear Control Switch harness connector.
Turn the ignition on.
Measure the voltage of the Rear Fan Sense circuit.
What voltage is present?
  1. Above 5.1 Volts: Go To 4
  2. Below 0.25 Volts: Go To 5
  3. Between 0.25 & 5.1 Volts: Go To 6
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4 Turn the ignition off.
Disconnect the ATC C1 harness connector.
Disconnect the Rear Booster Fan Rear Control Switch harness connector.
Turn the ignition on.
Measure the voltage between the Rear Fan Sense circuit and ground.
Is the voltage above 0.2 volts?
  1. Yes: Repair the Rear Fan Sense circuit for a short to voltage.

    Perform BODY VERIFICATION TEST VER-1 .

  2. No: Replace the Automatic Temperature Control (ATC) in accordance with the Service Information.

    Perform BODY VERIFICATION TEST VER-1 .

 All
5 Turn the ignition off.
Disconnect the ATC C1 harness connector.
Disconnect the Rear Booster Fan Rear Control Switch harness connector.
Measure the resistance of the Rear Fan Sense circuit between the ATC C1 harness connector and the Rear Booster Fan Rear Control Switch harness connector.
Is the resistance below 5.0 ohms?
  1. Yes: Replace the Automatic Temperature Control (ATC) in accordance with the Service Information.

    Perform BODY VERIFICATION TEST VER-1 .

  2. No: Repair the Rear Fan Sense circuit for an open.

    Perform BODY VERIFICATION TEST VER-1 .

 All
6 Turn the ignition off.
Disconnect the ATC C1 harness connector.
Disconnect the Rear Booster Fan Rear Control Switch harness connector.
Measure the resistance between the Rear Fan Sense Supply circuit and the Rear Fan Sense circuit.
Is the resistance above 100K ohms?
  1. Yes: Go To 7
  2. No: Repair the Rear Fan Sense Supply circuit for a short to the Rear Fan Sense circuit.

    Perform BODY VERIFICATION TEST VER-1 .

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7 Turn the ignition off.
Disconnect the ATC C2 harness connector.
Disconnect the Rear Booster Fan Rear Control Switch harness connector.
Measure the resistance of the Rear Fan Sense Return circuit between the ATC C2 harness connector and the Rear Booster Fan Rear Control Switch harness connector.
Is the resistance below 5.0 ohms?
  1. Yes: Go To 8
  2. No: Repair the Rear Fan Sense Return circuit for an open.

    Perform BODY VERIFICATION TEST VER-1 .

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8 Turn the ignition off.
Reconnect all previously disconnected components.
Connect 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.
Select the following Lab Scope settings:
Set the time to 10ms/Div.
Set the voltage range to +10.0v.
Set the Offset to 2.00v.
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. Turn the Rear Booster Fan Rear Control Switch to the AUTO position.
Using the X10 Scope Probe, back probe the Rear Fan Sense circuit in the Rear Booster Fan Rear Control Switch harness connector.
Slowly turn the Rear Booster Fan Rear Control through each of the 12 switch positions (Auto, Off, & Spds 1 -10) while observing the DRBIII® display.
The voltage should increase gradually from approx. 0.06 to 4.9 volts with no spikes or signal drop out.
Was any loss of signal observed while rotating the switch?
  1. Yes: Replace the Rear Booster Fan Rear Control Switch in accordance with the Service Information.

    Perform BODY VERIFICATION TEST VER-1 .

  2. No: Replace the Automatic Temperature Control (ATC) in accordance with the Service Information.

    Perform BODY VERIFICATION TEST VER-1 .

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