Pinpoint Test F: The Subwoofer Is Inoperative - CDX6 Audiophile

WARNING: This page is about a different car, the 2004 Ford Ranger. However, it is still accessible from the selected car via links, so may be relevant.

F1 CHECK CIRCUIT 828 (VT/LB) FOR VOLTAGE
- Key in OFF position.
- Disconnect: Subwoofer Amplifier C3041.
- Measure the voltage between the subwoofer amplifier C3041 pin 4, circuit 828 (VT/LB), harness side and ground; and between the subwoofer amplifier C3041 pin 5, circuit 828 (VT/LB), harness side and ground.
  
  Fig 1: Checking Circuit 828 (VT/LB) For Voltage
  Courtesy of FORD MOTOR CO.
- Are the voltages greater than 10 volts?
1. Yes : GO to F2.
2. No : REPAIR the circuit. TEST the system for normal operation.
F2 CHECK CIRCUIT 694 (BK/LG) FOR AN OPEN
- Measure the resistance between the subwoofer amplifier C3041 pin 2, circuit 694 (BK/LG), harness side and ground; and between the subwoofer amplifier C3041 pin 3, circuit 694 (BK/LG), harness side and ground.
  
  Fig 2: Checking Circuit 694 (BK/LG) For An Open
  Courtesy of FORD MOTOR CO.
- Are the resistances less than 5 ohms?
1. Yes : GO to F3.
2. No : REPAIR the circuit. TEST the system for normal operation.
F3 CHECK THE AUDIO SIGNAL TO THE SUBWOOFER SPEAKER
- Connect: Subwoofer Amplifier C3041.
- Disconnect: Subwoofer Speaker C3020.
- Key in ON position.
- While adjusting the volume control with the audio unit on, measure the voltage between the subwoofer speaker C3020 pin 1, circuit 176 (PK/LG), harness side and subwoofer speaker C3020 pin 2, circuit 179 (OG/RD), harness side.
  
  Fig 3: Checking Audio Signal To Subwoofer Speaker
  Courtesy of FORD MOTOR CO.
- Is there a fluctuating AC voltage present?
1. Yes : INSTALL a new subwoofer speaker enclosure. REFER to SPEAKERS .
2. No : GO to F4.
F4 CHECK THE AUDIO SIGNAL CIRCUITS TO THE AMPLIFIER
- Key in OFF position.
- Disconnect: Subwoofer Amplifier C3041.
- Key in START position.
- While adjusting the volume control with the audio unit on, measure the voltage between the subwoofer amplifier C3041 pin 8, circuit 172 (LB/RD), harness side and the subwoofer amplifier C3041 pin 7, circuit 169 (LG/BK), harness side.
  
  Fig 4: Checking Audio Signal Circuits To Amplifier
  Courtesy of FORD MOTOR CO.
- Is there a fluctuating AC voltage present?
1. Yes : GO to F6 .
2. No : GO to F5.

F5 CHECK THE AUDIO SIGNAL CIRCUITS FOR OPENS OR SHORTS TO GROUND

Key in OFF position.
Disconnect: Audio Unit C290b.

Measure the resistance between the audio unit C290b and the subwoofer amplifier C3041, and between the audio unit C290b and ground in the following groups:

Audio Unit Connector	Subwoofer Amplifier Connector
C290b pin 1 circuit 172 (LB/RD)	C3041 pin 8 circuit 172 (LB/RD)
C290b pin 2 circuit 169 (LG/BK)	C3041 pin 7 circuit 169 (LG/BK)
C290b pin 4 circuit 829 (WH/VT)	C3041 pin 1 circuit 829 (WH/VT)

Are the resistances less than 5 ohms between the audio unit and amplifier and greater than 10,000 ohms between the audio unit and ground?

Yes : REMOVE the audio unit and SEND it to an authorized repair facility. TEST the system for normal operation.
No : REPAIR the circuit(s) in question. TEST the system for normal operation.

F6 CHECK THE SUBWOOFER AUDIO SIGNAL CIRCUITS FOR OPENS OR SHORTS TO GROUND
- Key in OFF position.
- Examine the subwoofer amplifier harness between the subwoofer amplifier and the subwoofer speaker for opens and shorts.
- Is the harness OK?
1. Yes : REMOVE the subwoofer amplifier. SEND it to an authorized repair facility. TEST the system for normal operation.
2. No : REPAIR the circuit(s) in question. TEST the system for normal operation.