Pinpoint Test D: The Audio System Illumination Is Inoperative
WARNING: This page is about a different car, the 2007 Mercury Mariner and 2007 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.
CAUTION:
Use the correct probe adaptor(s) when making measurements. Failure to use the correct probe adaptor(s) may damage the connector.
- D1 CHECK FOR VOLTAGE ON CIRCUIT 19 (LB/RD)
- Key in OFF position.
- Disconnect: Audio Unit C290 (M100CD, CDX6), C240a (MACH 300) or C229a (Navigation)
- Place the headlamp switch in the PARK position.
- Move the instrument panel dimmer switch to the full illumination position.
- If equipped with M100CD or CDX6, measure the voltage between the audio unit C290-1, circuit 19 (LB/RD), harness side and ground.
- If equipped with MACH 300, measure the voltage between the audio unit C240a-3, circuit 19 (LB/RD), harness side and ground.
- If equipped with Navigation, measure the voltage between the audio unit C229a-4, circuit 19 (LB/RD), harness side and ground.
- Is the voltage greater than 10 volts?
- YES : Go to D2.
- NO : REPAIR the circuit. TEST the system for normal operation.
- D2 CHECK CIRCUIT 57 (BK) FOR AN OPEN
- If equipped with M100CD or CDX6, measure the resistance between the audio unit C290-2, circuit 57 (BK), harness side and ground.
- If equipped with MACH 300, measure the resistance between the audio unit C240a-4, circuit 57 (BK), harness side and ground.
- If equipped with Navigation, measure the resistance between the audio unit C229a-2, circuit 57 (BK), harness side and ground.
- Is the resistance less than 5 ohms?
- YES : INSTALL a new audio unit. REFER to INFORMATION AND ENTERTAINMENT SYSTEMS article. TEST the system for normal operation.
- NO : REPAIR the circuit. TEST the system for normal operation.