Pinpoint Test G: The Auxiliary Audio Control Is Inoperative - Steering Wheel Audio Control Switch(Es)

• Key in OFF position.
• Disconnect: Audio Unit.
• Measure the resistance between the audio unit C240a-14 (DM100) or C290a-18 (CD6), circuit 583 (YE), harness side and ground while pressing the steering wheel control switches as follows:
  STEERING WHEEL CONTROL SWITCH RESISTANCE
  
  

  Switch	Resistance Range
  VOL Down	69.27 -77.38 ohms
  VOL Up	198.5-217.61 ohms
  NEXT	419.4-467.5 ohms
  MODE	848.1-945.1 ohms
  No Buttons Pressed	4,560-5,080 ohms

• Are the resistances within specification? 

Yes 

REMOVE the audio unit and SEND it to an authorized audio system repair facility. TEST the system for normal operation.

No 

GO to G2.

• Disconnect: Clockspring C218a.
• Disconnect: Audio Unit.
• Measure the resistances between the audio unit C240a-14 (DM100), or C290a-18 (CD6), circuit 583 (YE), harness side and the clockspring C218a-3, circuit 583 (YE), harness side; and between the audio unit C240a-14 (DM100), or C290a-18 (CD6), circuit 583 (YE), harness side and ground.
  Fig 1: Checking Circuit 583 (YE) For Open Or Short To Ground

  Courtesy of FORD MOTOR CO.
• Is the resistance less than 5 ohms between the audio unit and the clockspring; and greater than 10,000 ohms between the audio unit and ground? 

Yes 

GO to G3.

No 

REPAIR the circuit. TEST the system for normal operation.

• Measure the resistance between the clockspring C218a-5, circuit 848 (DG/OG), harness side and ground.
  Fig 2: Checking Ground Circuit 848 (DG/OG)

  Courtesy of FORD MOTOR CO.
• Is the resistance less than 5 ohms? 

Yes 

GO to G4.

No 

GO to  G6.

• Remove the driver air bag module. Refer to DUAL-STAGE DRIVER-SIDE AIR BAG MODULE .
• Disconnect: Steering Wheel Control Switch Harness.
• Measure the resistance between the steering wheel control switch C2983, pin 4, circuit 583 (YE), harness side and the clockspring C218a pin 3, circuit 583 (YE), component side.
  Fig 3: Checking Signal Circuit In Steering Wheel Control Switch Harness

  Courtesy of FORD MOTOR CO.
• Is the resistance less than 5 ohms? 

Yes 

GO to G5.

No 

INSTALL a new clockspring. REFER to CLOCKSPRING . TEST the system for normal operation. INSTALL the air bag. REFER to DUAL-STAGE DRIVER-SIDE AIR BAG MODULE .

• Measure the resistance between the steering wheel control switch C2983, pin 3 circuit 848 (DG/OG), harness side and the clockspring C218a pin 5, circuit 848 (DG/OG), component side.
  Fig 4: Checking Ground Circuit In Steering Wheel Control Switch Harness

  Courtesy of FORD MOTOR CO.
• Is the resistance less than 5 ohms? 

Yes 

INSTALL a new steering wheel control switch(es). REFER to STEERING WHEEL AUDIO CONTROLS . TEST the system for normal operation. INSTALL the air bag. REFER to DUAL-STAGE DRIVER-SIDE AIR BAG MODULE .

No 

INSTALL a new clockspring. REFER to CLOCKSPRING . TEST the system for normal operation. INSTALL the air bag. REFER to DUAL-STAGE DRIVER-SIDE AIR BAG MODULE .

• Disconnect: Powertrain Control Module (PCM) C175b.
• Measure the resistance between the clockspring C218a-5, circuit 848 (DG/OG), harness side and the PCM C175b-30, circuit 848 (DG/OG), harness side.
  Fig 5: Checking Ground Circuit 848 (DG/OG)

  Courtesy of FORD MOTOR CO.
• Is the resistance less than 5 ohms? 

Yes 

GO to G7.

No 

REPAIR the circuit. TEST the system for normal operation.

• Disconnect all the PCM connectors.
• Check for:
  • corrosion.
  • pushed-out pins.
• Connect all the PCM connectors and make sure they seat correctly.
• Operate the system and verify the concern is still present.
• Is the concern still present? 

Yes 

INSTALL a new PCM. REFER to POWERTRAIN CONTROL MODULE (PCM) (4.0L SOHC) or POWERTRAIN CONTROL MODULE (PCM) (4.6L). CLEAR the DTCs. REPEAT the PCM self-test.

No 

The system is operating correctly at this time. Concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.