Pinpoint Test R: The Fog Lamps Are On Continuously

WARNING: This page is about a different car, the 2009 Ford Mustang. However, it is still accessible from the selected car via links, so may be relevant.

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

R1 RETRIEVE THE RECORDED DTCs FROM THE SJB SELF-TEST
- Key in OFF position.
- Retrieve the recorded results from the SJB self-test.
- Was DTC B2030 or B2254 present?
1. YES : For DTC B2254, go to R2.
  For DTC B2030, go to R4.
2. NO : Go to R6.
R2 CHECK THE HEADLAMP SWITCH
- Key in OFF position.
- Disconnect: Headlamp Switch C205
- Carry out the headlamp switch component test. Refer to COMPONENT TESTING.
- Is the headlamp switch OK?
1. YES : Go to R3.
2. NO : INSTALL a new headlamp switch. CLEAR the DTCs. REPEAT the self-test.
R3 CHECK CIRCUIT 1669 (OG/LG) FOR A SHORT TO GROUND
- Disconnect: SJB C2280b
- Measure the resistance between the headlamp switch C205-6, circuit 1669 (OG/LG), harness side and ground.
- Is the resistance greater than 10,000 ohms?
1. YES : Go to R9.
2. NO : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
R4 CHECK THE SJB
- Disconnect: SJB C2280c
- Key in ON position.
- Do the fog lamps continue to illuminate?
1. YES : Go to R5.
2. NO : Go to R9.
R5 CHECK CIRCUIT 1347 (DB/WH) FOR A SHORT TO GROUND
- Key in OFF position.
- Disconnect: BEC C1035a
- Key in ON position.
- Do the fog lamps continue to illuminate?
1. YES : INSTALL a new BEC. CLEAR the DTCs. REPEAT the self-test.
2. NO : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
R6 CHECK THE FOG LAMP RELAY
- Disconnect: Fog Lamp Relay
- Key in ON position.
- Do the fog lamps continue to illuminate?
1. YES : Go to R7.
2. NO : INSTALL a new fog lamp relay. TEST the system for normal operation.
R7 CHECK CIRCUIT 2024 (VT/OG) FOR A SHORT TO VOLTAGE
- Key in OFF position.
- Disconnect: BEC C1035a
- Key in ON position.
- Do the fog lamps continue to illuminate?
1. YES : Go to R8.
2. NO : REPAIR the circuit. TEST the system for normal operation.
R8 CHECK CIRCUITS 1721 (LB/BK) (LH FOG LAMP) AND 1776 (TN/OG) (RH FOG LAMP) FOR A SHORT TO VOLTAGE
- Key in OFF position.
- Disconnect: BEC C1035c
- Key in ON position.
- For 4.0L or 4.6L, measure the voltage between the LH fog lamp C152-1, circuit 1721 (LB/BK), harness side and ground; or between the RH fog lamp C162-1, circuit 1776 (TN/OG), harness side and ground.
- For 5.4L, measure the voltage between the LH fog lamp C1322-A, circuit 1721 (LB/BK), harness side and ground; or between the RH fog lamp C1323-A, circuit 1776 (TN/OG), harness side and ground.
- Is any voltage present?
1. YES : REPAIR the circuit in question. TEST the system for normal operation.
2. NO : INSTALL a new BEC. TEST the system for normal operation.
R9 CHECK FOR CORRECT SJB OPERATION
- Key in OFF position.
- Disconnect all the SJB connectors.
- Check for:
  - corrosion
  - damaged pins
  - 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?
1. YES : INSTALL a new SJB. REFER to MULTIFUNCTION ELECTRONIC MODULES . TEST the system for normal operation.
2. 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.