Pinpoint Test A: The Compass Is Inaccurate/Inoperative

WARNING: This page is about a different car, the 2006 Mercury Grand Marquis and 2006 Ford Crown Victoria. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Always set the zone and calibrate the compass before replacing an inaccurate compass.

NOTE: After installing a new compass, always set the zone and calibrate.

A1 CHECK THE OVERHEAD COMPASS DISPLAY
- Key in ON position.
- Check the overhead display.
- Does the overhead compass display remain on after prove out?
Yes : GO to A3.

No : GO to A2.
A2 CHECK THE COMPASS MODE
- Press and release the SELECT switch on the overhead console.
- Does the overhead compass display turn on?
Yes : If the compass display turns on correctly, GO to A3. If the compass display turns on, but the heading is inoperative/inaccurate or the display indicates VAR, GO to A4. If the compass display turns on, but it does not display all directions, or indicates CAL, GO to A5.

No : GO to A7.
A3 CHECK THE COMPASS DIMMING
- Turn the headlamp switch to the parking lamps ON position.
- Does the compass display dim?
Yes : TURN the headlamp switch to the OFF position. GO to A4.

No : TURN the headlamp switch to the OFF position. GO to A8.
A4 CHECK THE COMPASS ZONE SETTING
- Set the compass to the correct zone for your location. Refer to COMPASS ZONE ADJUSTMENT .
- Does the zone adjustment set correctly?
Yes : GO to A5.

No : INSTALL a new overhead console. REFER to INSTRUMENT PANEL AND CONSOLE . TEST the system for normal operation.
A5 CALIBRATE THE COMPASS
- Calibrate the compass. Refer to COMPASS CALIBRATION .
- Is the compass calibrated correctly?
Yes : GO to A6.

No : INSTALL a new overhead console. REFER to INSTRUMENT PANEL AND CONSOLE . TEST the system for normal operation.
A6 CHECK THE COMPASS ACCURACY
- Position the vehicle at each of the 8 directions (N, NE, E, SE, S, SW, W, NW) and verify that the displayed heading is accurate. The vehicle must be stationary for at least 10 seconds at each direction.
- Is the compass display accurate in each direction?
Yes : The compass is OK. REVIEW the operation of the compass with the customer.

No : INSTALL a new overhead console. REFER to INSTRUMENT PANEL AND CONSOLE . TEST the system for normal operation.
A7 CHECK THE VOLTAGE SUPPLY TO THE OVERHEAD CONSOLE
- Key in OFF position.
- Disconnect: Overhead Console C930.
- Key in ON position.
- Measure the voltage between the overhead console C930-1, circuit 964 (DB/LG), harness side and ground.
  
  Fig 1: Measuring Voltage Between Overhead Console C930-1 And Ground
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
Yes : TURN the key to the OFF position. GO to A9.

No : VERIFY the CJB fuse 15 (7.5A) is OK. If OK, REPAIR the circuit. TEST the system for normal operation.
A8 CHECK THE DIMMING CIRCUIT
- Key in OFF position.
- Disconnect: Overhead Console C930.
- Turn the headlamp switch to the parking lamps ON position.
- Measure the voltage between the overhead console C930-4, circuit 484 (OG/BK), harness side and ground while rotating the instrument panel dimmer switch.
  
  Fig 2: Measuring Voltage Between Overhead Console C930-4 And Ground
  Courtesy of FORD MOTOR CO.
- Does the voltage vary between 0 and 10 volts?
Yes : GO to A9.

No : REFER to INSTRUMENT CLUSTER AND PANEL ILLUMINATION for further diagnosis of the instrument cluster and panel illumination.
A9 CHECK CIRCUIT 676 (PK/OG) FOR OPEN
- Measure the resistance between the overhead console C930-2, circuit 676 (PK/OG), harness side and ground.
  
  Fig 3: Measuring Resistance Between Overhead Console C930-2 And Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
Yes : INSTALL a new overhead console. REFER to INSTRUMENT PANEL AND CONSOLE . TEST the system for normal operation.

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