Pinpoint Test O: The Air Bag Warning Indicator Is Never/Always On

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

O1 RETRIEVE AND RECORD THE RESTRAINT CONTROL MODULE (RCM) DTCS FROM BOTH THE CONTINUOUS AND ON-DEMAND SELF-TESTS
- Check the recorded RCM DTCs from the continuous and on-demand self-tests.
- Are any RCM DTCs present?
- Yes : REFER to SUPPLEMENTAL RESTRAINT SYSTEM to continue diagnosis of the DTCs.
- No : GO to O2.
O2 CARRY OUT THE INSTRUMENT CLUSTER WARNING LAMPS AND CHIME ACTIVE COMMAND USING THE DIAGNOSTIC TOOL
- Key in ON position.
- Enter the following diagnostic mode on the diagnostic tool: Instrument Cluster Active Command.
- Select the instrument cluster warning lamps and chime active command. Trigger the all lamps active command on and off. Observe the air bag warning indicator.
- Does the air bag warning indicator illuminate when triggered on and turn off when triggered off?
- Yes : If the air bag indicator is never on, GO to O5.
  If the air bag indicator is always on, GO to O3.
- No : GO to O6.
O3 CHECK THE RCM CONTROL
- Deactivate the air bag system. Refer to SUPPLEMENTAL RESTRAINT SYSTEM .
- Key in OFF position.
- Disconnect: RCM C310a.
- Connect a fused (10A) jumper wire between the RCM C310a-19, circuit 608 (BK/YE), harness side and ground.
  
  Fig 1: Connecting Fused (10A) Jumper Wire Between RCM C310a-19, Circuit 608 (BK/YE), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
- Key in ON position.
- Does the air bag indicator lamp illuminate after the instrument cluster proves out?
- Yes : GO to O8.
- No : GO to O4.
O4 CHECK CIRCUIT 608 (BK/YE) FOR AN OPEN
- Key in OFF position.
- Disconnect: Instrument Cluster C220b.
- Measure the resistance between the instrument cluster C220b-3, circuit 608 (BK/YE), harness side and the RCM C310a-19, circuit 608 (BK/YE), harness side.
  
  Fig 2: Checking Circuit 608 (BK/YE) For An Open
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes : GO to O7.
- No : REPAIR the circuit. TEST the system for normal operation.
O5 ISOLATE THE RCM
- Key in OFF position.
- Deactivate the air bag system. Refer to SUPPLEMENTAL RESTRAINT SYSTEM .
- Disconnect: RCM C310a.
- Observe the air bag warning indicator.
- Key in ON position.
- Does the air bag warning indicator illuminate?
- Yes : GO to O8.
- No : GO to O6.
O6 CHECK CIRCUIT 608 (BK/YE) FOR A SHORT TO GROUND
- Key in OFF position.
- Disconnect: Instrument Cluster C220b.
- Measure the resistance between the instrument cluster C220b-3, circuit 608 (BK/YE), harness side and ground.
  
  Fig 3: Measuring Resistance Between Instrument Cluster C220b-3, Circuit 608 (BK/YE), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance greater than 10,000 ohms?
- Yes : GO to O7.
- No : REPAIR the circuit. TEST the system for normal operation.
O7 CHECK FOR CORRECT INSTRUMENT CLUSTER OPERATION
- Disconnect all the instrument cluster connectors.
- Check for:
  - corrosion
  - pushed-out pins
- Connect all the instrument cluster 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 instrument cluster. REFER to INSTRUMENT CLUSTER . 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.
O8 CHECK FOR CORRECT RCM OPERATION
- Disconnect all the RCM connectors.
- Check for:
  - corrosion
  - pushed-out pins
- Connect all the RCM 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 RCM. REFER to SUPPLEMENTAL RESTRAINT SYSTEM . 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.