Pinpoint Test

CHECK THE OPERATION OF THE REAR WINDOW DEFROST SYSTEM
1. With the engine running, activate the rear window defrost.
2. Using an infrared temperature gun or equivalent, measure the temperature of the rear window glass for approximately 30 seconds, noting changes in temperature.
  - Does the temperature of the rear window glass rise?
  - Yes: GO to step 2 .
  - No: REFER to SYMPTOM CHART: GLASS, FRAMES AND MECHANISMS and diagnose the rear window defrost system.
CHECK THE OPERATION OF THE HEATED EXTERIOR REAR VIEW MIRRORS
1. With the rear window defrost activated, using an infrared temperature gun or equivalent, measure the temperature of the Right Hand (RH) and Left Hand (LH) exterior rear view mirror glass for approximately 30 seconds, noting changes in temperature.
  - Does at least one heated mirror glass operate correctly?
  - Yes: GO to step 4 .
  - No: VERIFY that Battery Junction Box (BJB) fuse 50 (15A) is OK. If OK, GO to step 3 . If not OK, REFER to the SYSTEM WIRING DIAGRAMS to identify the possible cause of the circuit short.
CHECK FOR VOLTAGE TO Battery Junction Box (BJB) FUSE 50 (15A)
1. Verify Battery Junction Box (BJB) fuse 50 (15A) is installed.
2. Ignition ON.
3. With the engine running, activate the rear window defrost.
4. Measure:
  
  Fig 1: Checking Voltage Of Battery Junction Box Fuse 50 (15A)
  Courtesy of FORD MOTOR CO.
  - Is the voltage greater than 11 volts?
  - Yes: REPAIR circuit CRD17 (GY).
  - No: REPAIR circuit CRD06 (BN/YE).
CHECK THE VOLTAGE TO THE INOPERATIVE HEATED EXTERIOR REAR VIEW MIRROR GLASS
1. Ignition OFF.
2. Disconnect: Inoperative Left Hand (LH) or Right Hand (RH) Heated Exterior Mirror.
3. Ignition ON.
4. With the engine running, activate the rear window defrost.
5. For inoperative Left Hand (LH) heated mirror, measure:
  
  Fig 2: Left Hand (LH) Heated Mirror Connector Reference Chart
  Courtesy of FORD MOTOR CO.
6. For inoperative Right Hand (RH) heated mirror, measure:
  
  Fig 3: Right Hand (RH) Exterior Mirror Connector Reference Chart
  Courtesy of FORD MOTOR CO.
  - Is the voltage greater than 11 volts?
  - Yes: GO to step 5 .
  - No: REPAIR the circuit.
CHECK THE INOPERATIVE EXTERIOR REAR VIEW MIRROR GROUND CIRCUIT FOR AN OPEN
1. Ignition OFF.
2. For inoperative Left Hand (LH) heated mirror, measure:
  
  Fig 4: Left Hand (LH) Exterior Mirror Connector Reference Chart
  Courtesy of FORD MOTOR CO.
3. For inoperative Right Hand (RH) heated mirror, measure:
  
  Fig 5: Right Hand (RH) Exterior Mirror Connector Reference Chart
  Courtesy of FORD MOTOR CO.
  - Is the resistance less than 3 ohms?
  - Yes: CHECK the Left Hand (LH) or Right Hand (RH) exterior mirror jumper harness between the vehicle harness and the exterior mirror motors for shorted circuits and damaged or pushed-out pins. If the jumper harness is not OK, REPAIR the jumper harness. If the jumper harness cannot be repaired, INSTALL a new Left Hand (LH) or Right Hand (RH) exterior mirror. REFER to EXTERIOR MIRROR . If the jumper harness is OK, INSTALL a new exterior mirror glass. REFER to EXTERIOR MIRROR GLASS .
  - No: REPAIR the circuit.