Body and Paint

Seat Belt Systems - Diagnosis and Testing

21steps
~126min
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Symptom Chart

The diagnosis in this manual assumes a certain level of skill and knowledge of Ford-approved diagnostic procedures.
REFER TO: Diagnostic Methods (100-00 General Information, Description and Operation).

Preliminary Inspection

Before diagnosing or repairing the seat belt system, check the following:

  • Seat belt webbing integrity (torn, frayed, cut or stretched)
  • Seat Belt Buckle and Tongue Assembly (latching and unlatching, foreign objects)

Symptom Chart: Seat Belt System

Symptom Chart


Condition Possible Sources Action
Unbuckled seat belt warning indicator does not work
  • Blown Indicator
  • Wiring, Terminals or Connectors
  • PCM
  • RCM
  • If the airbag indicator is illuminated,
    REFER TO: Supplemental Restraint System (SRS) (501-20B Supplemental Restraint System, Diagnosis and Testing).
    If the airbag warning indicator is not illuminated, REFER TO: Instrument Cluster, Message Center and Audible Warnings (413-01 Instrument Cluster, Message Center and Audible Warnings, Diagnosis and Testing).
Unbuckled seat belt chime does not work
  • Wiring, Terminals or Connectors
  • Seat Belt Switch
  • PCM
  • RCM
  • If the airbag indicator is illuminated,
    REFER TO: Supplemental Restraint System (SRS) (501-20B Supplemental Restraint System, Diagnosis and Testing).
    If the airbag warning indicator is not illuminated, REFER TO: Instrument Cluster, Message Center and Audible Warnings (413-01 Instrument Cluster, Message Center and Audible Warnings, Diagnosis and Testing).
Seat belt webbing does not extend or applies excessive pressure to the occupant during use
  • Seat belt retractor is in web sensing mode
RELEASE the locked seat belt retractor.
Refer to: Releasing a Locked Seat Belt Retractor (501-20A Seat Belt Systems, General Procedures).
  • Interior trim installed incorrectly
CORRECT the trim panel installation. Refer to Section 501-05.
  • The seat belt retractor is in Automatic Locking Retractor (ALR) mode.
  • Seat belt retractor with internal jam
PERFORM the appropriate functional test. Refer to Functional Test - Seat Belt Pretensioner, Functional Test - Seat Belt Retractor, Automatic Locking Retractor (ALR) Mode, or Functional Test - Seat Belt Retractor, Road Test, as applicable. INSTALL new components as necessary.
Seat belt webbing does not retract or excessively slackens during use.
  • Seat belt webbing twisted or routed incorrectly
CORRECT a twisted seat belt webbing.
REFER TO: Seat Belt Buckle Rotates on the Belt (Seat Belt Systems 501-20A, General Procedures).
REFER TO: Seat Belt Twisted in the Seat Belt Guide (Seat Belt Systems 501-20A, General Procedures).
  • Interior trim installed incorrectly
CORRECT the trim panel installation. Refer to Section 501-05.
  • Seat belt retractor with internal jam
PERFORM the appropriate functional test. Refer to Functional Test - Seat Belt Pretensioner, Functional Test - Seat Belt Retractor, Automatic Locking Retractor (ALR) Mode, or Functional Test - Seat Belt Retractor, Road Test, as applicable. INSTALL new components as necessary.
Belt-Minder® feature does not function
  • Belt-Minder® Function Deactivated
  • Wiring, Terminals or Connectors
  • To activate the Belt-Minder® feature, REFER TO the Seats and Restraints section of the Owner's Literature or
    REFER TO: Belt-Minder Deactivation/Activation (413-01 Instrument Cluster, Message Center and Audible Warnings, General Procedures).
  • If Belt-Minder® is activated, CHECK the Belt-Minder® feature for a malfunction.
    REFER TO: Instrument Cluster, Message Center and Audible Warnings (413-01 Instrument Cluster, Message Center and Audible Warnings, Diagnosis and Testing).
Seat belt latch plate rotates on the seat belt webbing.
  • Seat belt webbing twisted or routed incorrectly

  • Refer to: Seat Belt Tongue Rotates on Belt (501-20A Seat Belt Systems, General Procedures).
Seat belt webbing is twisted in the seat belt guide.
  • Seat belt webbing twisted or routed incorrectly

  • Refer to: Seat Belt Twisted in Seat Belt Guide (501-20A Seat Belt Systems, General Procedures).
Seat belt webbing is dirty or soiled
  • Seat belt webbing dirty or soiled

  • Refer to: Cleaning Seat Belts (501-20A Seat Belt Systems, General Procedures).

Functional Test - Seat Belt Buckle and Tongue

  1. During the latching sequence, check the following:
  • Tongue insertion does not require excessive force.
  • A click is heard when the buckle latches onto the tongue.
  1. Check the system integrity by pulling firmly on the seat belt webbing.
  2. Unfasten the seat belt by fully pressing the seat belt buckle release button and allowing the seat belt to unlatch and retract.
  3. During the unlatching process, check the following:
  • Button press does not require excessive force.
  • The tongue releases easily from the buckle.
  1. Repeat the above steps 3 times.
  2. If the functional check reveals a fault, install a new seat belt buckle or seat belt retractor as necessary.

Functional Test - Seat Belt Retractor

  1. Extend and retract the seat belt webbing between the fully extended and stowed positions.
  2. Make sure the seat belt retractor operates without excessive force or binding.
  3. Install a new seat belt retractor if any problems are found or the customer complaint is confirmed.

Functional Test - Seat Belt Retractor Mode, Automatic Locking Retractor (ALR)

  1. Position the seatback upright (if adjustable).
  2. Set the seat belt shoulder height adjuster (if equipped) to the lowest or highest position.
  3. Fasten the seat belt.
  4. Pull out the seat belt webbing until the Automatic Locking Retractor (ALR) function is activated.
  5. Allow the seat belt to retract fully.
  6. Pull the seat belt webbing to make sure the seat belt retractor remains in Automatic Locking Retractor (ALR) mode. If the seat belt retractor does not lock, install a new seat belt retractor.
  7. Unlatch the seat belt and allow the webbing to retract to its original position.
  8. Extend and retract the seat belt webbing to check that the seat belt retractor automatically returns from Automatic Locking Retractor (ALR) mode. If the seat belt retractor remains locked in Automatic Locking Retractor (ALR) mode, install a new seat belt retractor.

Functional Test - Seat Belt Retractor, Road Test Inspection

  1. Fasten the seat belts and proceed to a safe area.
  2. Accelerate to 24 km/h.
  3. Grasp the shoulder belts, lean forward and apply the brakes, applying maximum braking without skidding.
  4. Seat belts must latch with minimal webbing tension.
  5. If all seat belt retractors lock, verify that the seat belt retractors operate correctly. If any seat belt retractor does not lock, install new seat belt retractor(s).

Test yourself

A quick Ford Fusion quiz: every answer comes with an explanation and a link to the manual page.