Pinpoint Test H: The Subwoofer is Inoperative: Testing

WARNING: This page is about a different car, the 2005 Mercury Montego, 2005 Ford Freestyle, and 2005 Ford Five Hundred. However, it is still accessible from the selected car via links, so may be relevant.

H1 CHECK SUBWOOFER OPERATION
- Key in ON position.
- Turn on the audio control unit.
- Does the subwoofer sound operate correctly?
- Yes : The system is operating OK.
- No : GO to H2.
H2 CHECK CIRCUIT 174 (GY/BK) FOR VOLTAGE
- Key in OFF position.
- Disconnect: Subwoofer Amplifier C3041 or C466a.
- Key in ON position.
- Turn on the audio control unit.
- Measure the voltage between the subwoofer amplifier C3041-1 or C466a-1, circuit 174 (GY/BK), harness side and ground.
  
  Fig 1: Measuring Voltage Between Connector Terminal And Ground
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 4.1 volts?
- Yes : GO to H3.
- No : GO to H8.
H3 CHECK CIRCUIT 1678 (WH/VT) FOR VOLTAGE
- Measure the voltage between the subwoofer amplifier C3041-5 or C466a-5, circuit 1678 (WH/VT), harness side and ground.
  
  Fig 2: Measuring Voltage Between Subwoofer Amplifier C3041-5 Or C466A-5 Circuit 1678 (WH/VT)
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
- Yes : GO to H4.
- No : REPAIR the circuit. TEST the system for normal operation.
H4 CHECK CIRCUIT 1204 (BK/OG) FOR AN OPEN
- Measure the resistance between the subwoofer amplifier C3041-2 or C466a-2, circuit 1204 (BK/OG), harness side and ground.
  
  Fig 3: Measuring Resistance Between Subwoofer Amplifier C3041-2 Or C466A-2 Circuit 1204 (BK/OG)
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes : GO to H5.
- No : REPAIR the circuit. TEST the system for normal operation.
H5 CHECK FOR AN OUTPUT SIGNAL FROM THE AUDIO CONTROL UNIT
- Key in ON position.
- Turn the audio control unit on.
- Measure the voltage between the subwoofer amplifier C3041-7 or C466a-7, circuit 176 (PK/LG), harness side and the subwoofer amplifier C3041-8 or C466a-8, circuit 179 (OG/RD), harness side.
  
  Fig 4: Measuring Voltage Between Subwoofer Amplifier C3041-7 Or C466A-7 Circuit 176 (PK/LG)
  Courtesy of FORD MOTOR CO.
- Is there a fluctuating AC voltage?
- Yes : GO to H11.
- No : GO to H6.
H6 CHECK CIRCUITS 176 (PK/LG) AND 179 (OG/RD) FOR AN OPEN
- Key in OFF position.
- Disconnect: Audio Control Unit C240b.
- Measure the resistances between the subwoofer amplifier C3041-7 or C466a-7, circuit 176 (PK/LG), harness side and the audio control unit C240b-1, circuit 176 (PK/LG), harness side; and between subwoofer amplifier C3041-8 or C466a-8, circuit 179 (OG/RD), harness side and the audio control unit C240b-2, circuit 179 (OG/RD), harness side.
  
  Fig 5: Measuring Resistances Between Subwoofer Amplifier C3041-7 Or C466A-7 Circuit 176 (PK/LG)
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes : GO to H7.
- No : REPAIR the circuit in question. TEST the system for normal operation.
H7 CHECK CIRCUITS 176 (PK/LG) AND 179 (OG/RD) FOR AN OPEN
- Measure the resistances between the subwoofer amplifier C3041-7 or C466a-7, circuit 176 (PK/LG), harness side and ground; and between subwoofer amplifier C3041-8, circuit 179 (OG/RD), harness side and ground.
  
  Fig 6: Measuring Resistances Between Subwoofer Amplifier C3041-7 Or C466A-7 Circuit 176 (PK/LG)
  Courtesy of FORD MOTOR CO.
- Is the resistance greater than 10,000 ohms?
- Yes : GO to H10.
- No : REPAIR the circuit in question. TEST the system for normal operation.
H8 CHECK CIRCUIT 174 (GY/BK) FOR AN OPEN
- Measure the resistance between the subwoofer amplifier C3041-1 or C466a-1, circuit 174 (GY/BK), harness side and the audio control unit C240b-4, circuit 174 (GY/BK), harness side
  
  Fig 7: Measuring Resistance Between Subwoofer Amplifier C3041-1 Or C466A-1 Circuit 174 (GY/BK)
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes : GO to H9.
- No : REPAIR the circuit. TEST the system for normal operation.
H9 CHECK CIRCUIT 174 (GY/BK) FOR AN OPEN AND A SHORT TO GROUND
- Measure the resistance between the subwoofer amplifier C3041-1 or C466a-1, circuit 174 (GY/BK), harness side and ground.
  
  Fig 8: Measuring Resistance Between Subwoofer Amplifier C3041-1 Or C466A-1 Circuit 174 (GY/BK)
  Courtesy of FORD MOTOR CO.
- Is the resistance greater than 10,000 ohms?
- Yes : GO to H10.
- No : REPAIR the circuit. TEST the system for normal operation.
H10 CHECK FOR CORRECT AUDIO CONTROL UNIT OPERATION
- Disconnect the audio control unit connectors.
- Check for:
  - corrosion
  - pushed-out pins
- Connect the audio control unit connectors and make sure they seat correctly.
- Operate the system and determine if the concern is still present.
- Is the concern still present?
- Yes : REMOVE the audio control unit. REFER to AUDIO UNIT . SEND it to an authorized repair facility. TEST the system for normal operation after the repair.
- No : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.
H11 CHECK FOR CORRECT SUBWOOFER AMPLIFIER OPERATION
- Disconnect the subwoofer amplifier connectors.
- Check for:
  - corrosion
  - pushed-out pins
- Connect the subwoofer amplifier connectors and make sure they seat correctly.
- Operate the system and determine if the concern is still present.
- Is the concern still present?
- Yes : REMOVE the subwoofer amplifier. REFER to AUDIO UNIT . SEND it to an authorized repair facility. TEST the system for normal operation after the repair.
- No : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. TEST the system for normal operation.