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

WARNING: This page is about a different car, the 2005 Ford Pickup, 2005 Ford F550 Super Duty, 2005 Ford F450 Super Duty, and 2005 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.

N1 VERIFY THE AIR BAG WARNING INDICATOR OPERATION
- Key in ON position.
  Observe the air bag warning indicator prove out.
- Does the air bag warning indicator prove out correctly?
- Yes : The system is OK.
- No : If the air bag warning indicator is never on, GO to N4.
If the air bag warning indicator is always on, GO to N2.
N2 CHECK CIRCUIT 608 (BK/YE)
- Deactivate the air bag system. Refer to SUPPLEMENTAL RESTRAINT SYSTEM .
- Key in OFF position.
- Disconnect: Restraint Control Module (RCM) C2041.
- Connect a fused (10A) jumper wire between the RCM C2041-20, circuit 608 (BK/YE), harness side and ground.
  
  Fig 1: Checking Circuit 608 (BK/YE)
  Courtesy of FORD MOTOR CO.
- Key in ON position.
- Does the air bag warning indicator illuminate?
- Yes : GO to N3.
- No : REFER to SUPPLEMENTAL RESTRAINT SYSTEM to continue diagnosis of the supplemental restraint system.
ACTIVATE the air bag system. REFER to SUPPLEMENTAL RESTRAINT SYSTEM .
N3 CHECK CIRCUIT 608 (BK/YE) FOR AN OPEN
- Key in OFF position.
- Disconnect: Instrument Cluster C220a.
- Measure the resistance between the instrument cluster C220a-14, circuit 608 (BK/YE), harness side and the RCM C2041-20, circuit 608 (BK/YE) harness side.
  
  Fig 2: Checking Circuit 608 (BK/YE) For Open
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes : GO to N6.
- No : REPAIR the circuit. ACTIVATE the air bag system. REFER to SUPPLEMENTAL RESTRAINT SYSTEM . TEST the system for normal operation.
N4 ISOLATE THE AIR BAG MODULE
- Key in OFF position.
- Deactivate the restraint control supplemental air bag system.
  Refer to SUPPLEMENTAL RESTRAINT SYSTEM .
- Disconnect: RCM C2041.
- Observe the air bag warning indicator.
- Key in ON position.
- Does the air bag warning indicator illuminate?
- Yes : GO to N7.
- No : GO to N5.
N5 CHECK CIRCUIT 608 (BK/YE) FOR A SHORT TO GROUND
- Key in OFF position.
- Disconnect: Instrument Cluster C220a.
- Measure the resistance between the instrument cluster C220a-14, circuit 608 (BK/YE), harness side and ground.
  
  Fig 3: Checking Circuit 608 (BK/YE) For Short To Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance greater than 10,000 ohms?
- Yes : GO to N6.
- No : REPAIR the circuit. TEST the system for normal operation.
ACTIVATE the restraint control supplemental air bag system. Refer to SUPPLEMENTAL RESTRAINT SYSTEM .
N6 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.
  ACTIVATE the restraint control supplemental air bag system. Refer to SUPPLEMENTAL RESTRAINT SYSTEM . TEST the system for normal operation.
- No : The system is operating correctly at this time. ACTIVATE the air bag system. REFER to SUPPLEMENTAL RESTRAINT SYSTEM . The concern may have been caused by a loose or corroded connector.
N7 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.
  ACTIVATE the restraint control supplemental air bag system. Refer to SUPPLEMENTAL RESTRAINT SYSTEM .
- No : The system is operating correctly at this time. Concern may have been caused by a loose or corroded connector. ACTIVATE the air bag system. REFER to SUPPLEMENTAL RESTRAINT SYSTEM .