Pinpoint Test B: The Audio System Illumination Is Inoperative - Front Or Rear Controls

CAUTION: Use the correct probe adaptor(s) when making measurements. Failure to use he correct probe adaptor(s) may damage the connector.

B1 CHECK CIRCUIT 1417 (LG/RD) FOR VOLTAGE
- Key in OFF position.
- Disconnect: Audio Unit C240a (front), or RICP C9025.
- Place the headlamp switch in the PARK position.
- Rotate the instrument panel dimmer switch to the full illumination position.
- Measure the voltage between the audio unit C240a-3 (front), circuit 1417 (LG/RD), harness side; or between the RICP C9025-17, circuit 1417 (LG/RD), harness side and ground.
  
  Fig 1: Checking Circuit 1417 (LG/RD) For Voltage
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
Yes : GO to B2.

No : REPAIR the circuit. TEST the system for normal operation.
B2 CHECK CIRCUIT 1205 (BK) FOR AN OPEN
- Measure the resistance between the audio unit C240a-4 (front) or the RICP C9025-7, circuit 1205 (BK), harness side and ground.
  
  Fig 2: Checking Circuit 1205 (Bk) For Open
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?

Yes : INSTALL a new RICP or SEND the audio unit to an authorized repair facility. REFER to INFORMATION AND ENTERTAINMENT SYSTEM . TEST the system for normal operation after the repair.

No : REPAIR the circuit. TEST the system for normal operation.