Pinpoint Test F: The Control Illumination Does Not Dim

CAUTION: Use the correct probe adaptor(s) when making measurements. Failure to use the correct probe adaptor(s) may damage the connector.

F1 CHECK THE EXTERIOR LAMP OPERATION
- Place the headlamp switch in the parking lamps ON position.
- Are the parking lamps illuminated?
Yes: GO to F2.

No: REFER to PINPOINT TEST R: ONE OR MORE PARKING, REAR, OR LICENSE PLATE LAMP IS INOPERATIVE to continue diagnosis of the parking lamps.
F2 CHECK THE INSTRUMENT PANEL DIMMER SWITCH CIRCUITRY FOR AN OPEN
- Key in OFF position.
- Disconnect: Instrument Panel Dimmer Switch C2065.
- Disconnect: SJB C2280d.
- Measure the resistance between the SJB C2280d-29, circuit 1403 (BK/WH), harness side and the instrument panel dimmer switch C2065-6, circuit 1403 (BK/WH), harness side; and between the SJB C2280d-22, circuit 1036 (BN/WH), harness side and the instrument panel dimmer switch C2065-4, circuit 1036 (BN/WH), harness side.
  
  Fig 1: Measuring Resistance Between SJB C2280d-29, Circuit 1403 (BK/WH), Harness Side & Instrument Panel Dimmer Switch C2065-6, Circuit 1403 (BK/WH) & Harness Side
  Courtesy of FORD MOTOR CO.
- Are the resistances less than 5 ohms?
Yes: GO to F3.

No: REPAIR the circuit in question. TEST the system for normal operation.
F3 CHECK THE INSTRUMENT PANEL DIMMER SWITCH CIRCUITRY FOR A SHORT TO GROUND
- Measure the resistance between the SJB C2280d-29, circuit 1403 (BK/WH), harness side and ground; and between the SJB C2280d-22, circuit 1036 (BN/WH), harness side and ground.
  
  Fig 2: Measuring Resistance Between SJB C2280d-29, Circuit 1403 (BK/WH), Harness Side & Ground
  Courtesy of FORD MOTOR CO.
- Are the resistances greater than 10,000 ohms?
Yes: GO to F4.

No: REPAIR the circuit in question. TEST the system for normal operation.
F4 CHECK THE INSTRUMENT PANEL DIMMER SWITCH CIRCUITRY FOR A SHORT TO VOLTAGE
- Key in ON position.
- Measure the voltage between the SJB C2280d-29, circuit 1403 (BK/WH), harness side and ground; and between the SJB C2280d-22, circuit 1036 (BN/WH), harness side and ground.
  
  Fig 3: Measuring Voltage Between SJB C2280d-29, Circuit 1403 (BK/WH), Harness Side & Ground
  Courtesy of FORD MOTOR CO.
- Is any voltage present?
Yes: REPAIR the circuit in question. TEST the system for normal operation.

No: GO to F5.
F5 CHECK FOR CORRECT INSTRUMENT PANEL DIMMER SWITCH OPERATION
- While rotating the instrument panel dimmer switch wheel from the low to the full illumination position, measure the resistance between the SJB C2280d-29, circuit 1403 (BK/WH), harness side and the SJB C2280d-22, circuit 1036 (BN/WH), harness side.
  
  Fig 4: Measuring Resistance Between SJB C2280d-29, Circuit 1403 (BK/WH), Harness Side And SJB C2280d-22, Circuit 1036 (BN/WH) & Harness Side
  Courtesy of FORD MOTOR CO.
- Does the resistance value change while rotating the instrument panel dimmer switch wheel?
Yes: GO to F6.

No: INSTALL a new instrument panel dimmer switch. REFER to EXTERIOR LIGHTING . TEST the system for normal operation.
F6 CHECK FOR CORRECT SJB OPERATION
- Disconnect all the SJB connectors.
- Check for:
  - corrosion
  - pushed-out pins
- Connect all the SJB 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 SJB. REFER to REMOVAL AND INSTALLATION . TEST the system for normal operation.

No: The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.