Pinpoint Test J: DTC B2633 Driver - Front Microphone Circuit Failure

WARNING: This page is about a different car, the 2005 Lincoln Navigator and 2005 Ford Expedition. However, it is still accessible from the selected car via links, so may be relevant.

J1 CHECK THE VOICE SIGNAL INPUT
- Key in OFF position.
- Disconnect: Navigation System Module C2279a.
- Key in ON position.
- Measure the voltage between the navigation system module C2279a pin 7, circuit 714 (VT), harness side and between the navigation system module C2279a pin 19, circuit 713 (WH), harness side while speaking loudly into the rear view mirror microphone.
  
  Fig 1: Measuring Voltage Between Navigation System Module C2279A Pin 7 Circuit 714 (VT)
  Courtesy of FORD MOTOR CO.
- Is any AC voltage indicated?
- Yes : GO to J6.
- No : GO to J2.
J2 CHECK CIRCUIT 194 (PK) FOR VOLTAGE
- Key in OFF position.
- Disconnect: Rear View Mirror C9012.
- Key in ON position.
- Measure the voltage between the rear view mirror C9012 pin 13, circuit 194 (PK), harness side and ground.
  
  Fig 2: Measuring Voltage Between Rear View Mirror C9012 Pin 13 Circuit 194 (PK)
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
- Yes : GO to J3.
- No : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
J3 CHECK CIRCUIT 875 (BK/LB) FOR AN OPEN
- Key in OFF position.
- Measure the resistance between the rear view mirror C9012 pin 2, circuit 875 (BK/LB), harness side and ground.
  
  Fig 3: Measuring Resistance Between Rear View Mirror C9012 Pin 2
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes : GO to J4.
- No : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

J4 CHECK CIRCUITS 713 (WH) AND 714 (VT) FOR AN OPEN OR A SHORT TO GROUND

Measure the resistance between the navigation system module C2279a pins, harness side and the rear view mirror C9012 pins, harness side; and between the navigation system module C2279a pins, harness side and ground as follows:

NAVIGATION SYSTEM MODULE CHART

Navigation System Module	Rear View Mirror	Circuit
C2279a-7	C9012-9	714 (VT)
C2279a-19	C9012-10	713 (WH)

Fig 4: Checking Circuits 713 (WH) And 714 (VT) For An Open Or A Short To Ground

Courtesy of FORD MOTOR CO.

Are the resistances less than 5 ohms between the navigation system module and the rear view mirror, and greater than 10,000 ohms between the navigation system module and ground?

Yes : GO to J5.
No : REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test.

J5 CHECK CIRCUITS 713 (WH) AND 714 (VT) FOR A SHORT TO VOLTAGE
- Key in ON position.
- Measure the voltage between the navigation system module C2279a pin 7, circuit 714 (VT), harness side and ground; and measure the voltage between the navigation system module C2279a pin 19, circuit 713 (WH), harness side and ground.
  
  Fig 5: Measuring Voltage Between Navigation System Module C2279A Pin 7 Circuit 714 (VT)
  Courtesy of FORD MOTOR CO.
- Is any voltage indicated?
- Yes : REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test.
- No : INSTALL a new interior rear view mirror. REFER to REAR VIEW MIRRORS . CLEAR the DTCs. REPEAT the self-test.
J6 CHECK FOR CORRECT NAVIGATION SYSTEM MODULE OPERATION
- Disconnect all the navigation system module connectors.
- Check for:
  - corrosion
  - pushed-out pins
- Connect all the navigation system module 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 navigation system module. REFER to NAVIGATION MODULE . CLEAR the DTCs. REPEAT the self-test.
- No : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.