Pinpoint Test AL: The Compass Is Inoperative

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

AL1 CHECK CIRCUIT 1003 (GY/YE) FOR BATTERY VOLTAGE
- Key in OFF position.
- Disconnect: Compass Sensor Module C909.
- Key in ON position.
- Measure the voltage between the compass sensor module C909-2, circuit 1003 (GY/YE), harness side and ground.
  
  Fig 1: Measuring Voltage Between Compass Sensor Module C909-2, Circuit 1003 (GY/YE), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
Yes

GO to AL2.

No

REPAIR the circuit. TEST the system for normal operation.
AL2 CHECK CIRCUIT 1203 (BK/LB) FOR AN OPEN
- Key in OFF position.
- Measure the resistance between the compass sensor module C909-1, circuit 1203 (BK/LB), harness side and ground.
  
  Fig 2: Measuring Resistance Between Compass Sensor Module C909-1, Circuit 1203 (BK/LB), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
Yes

GO to AL3.

No

REPAIR the circuit. TEST the system for normal operation.
AL3 CHECK CIRCUIT 702 (WH/BK) AND CIRCUIT 703 (WH/OG) FOR OPEN AND SHORT TO GROUND
- Disconnect: Instrument Cluster C220b.
- Measure the resistance between the compass sensor module C909-3, circuit 703 (WH/OG), harness side and the instrument cluster C220b-16, circuit 703 (WH/OG), harness side; and between the compass sensor module C909-3, circuit 703 (WH/OG), harness side and ground.
  
  Fig 3: Checking Circuit 702 (WH/BK) And Circuit 703 (WH/OG) For Open And Short To Ground (1 Of 2)
  Courtesy of FORD MOTOR CO.
- Measure the resistance between the compass sensor module C909-4, circuit 702 (WH/BK), harness side and the instrument cluster C220b-17, circuit 702 (WH/BK), harness side; and between the compass sensor module C909-4, circuit 702 (WH/BK), harness side and ground.
  
  Fig 4: Checking Circuit 702 (WH/BK) And Circuit 703 (WH/OG) For Open And Short To Ground (2 Of 2)
  Courtesy of FORD MOTOR CO.
- Are the resistances less than 5 ohms between the compass sensor module and the instrument cluster; and greater than 10,000 ohms between the compass sensor module and ground?
Yes

INSTALL a new compass sensor module. SET the zone. Refer to COMPASS ZONE ADJUSTMENT . CALIBRATE the compass. Refer to COMPASS CALIBRATION . TEST the system for normal operation.

No

REPAIR the circuit(s) in question. TEST the system for normal operation.