Reminder System Control Unit (MICU, Gauge Control Module) Input Test
Gauge Control Module (Tach)
  1. Turn the ignition switch OFF.
  1. Remove the gauge control module (tach).
  1. Disconnect the gauge control module (tach) 36P connector.
  1. Inspect the connector and socket terminals to be sure they are all making good contact.
    • If the terminals are bent, loose or corroded, repair them as necessary, and recheck the system.
    • If the terminals are OK, go to Step 10 .
  1. With the connector still disconnected, make these input tests at the connector.
    • If any test indicates a problem, find and correct the cause, then recheck the system.
    • If all the input tests prove OK, go to Step 11 .
    Cavity
    Wire
    Test condition
    Test: Desired result
    Possible cause if result is not obtained
    16
    BLK
    Under all conditions
    Check for continuity to ground: There should be continuity.
    • Poor ground (G503)
    • An open in the wire
    18
    WHT
    Under all conditions
    Check for voltage to ground: There should be battery voltage.
    • Blown No. 16 (15 A) fuse in the under-hood fuse/relay box
    • An open in the wire
    17
    LT BLU
    Ignition switch ON (II)
    Check for voltage to ground: There should be battery voltage.
    • Blown No. 10 (7.5 A) fuse in the under-dash fuse/relay box
    • An open in the wire

  1. Reconnect the gauge control module (tach) 36P connector, then make these input tests at the connector.
    • If any test indicates a problem, find and correct the cause, then recheck the system.
    • If all the input tests prove OK, go to Step 12 .
    Cavity
    Wire
    Test condition
    Test: Desired result
    Possible cause if result is not obtained
    28
    LT BLU
    Parking brake switch ON (lever pulled)
    Check for voltage to ground: There should be less than 1 V.
    • Faulty parking brake switch
    • An open in the wire
    Parking brake switch OFF (lever pushed)
    Check for voltage to ground: There should be 5 V or more.
    • Faulty parking brake switch
    • A short to ground in the wire

  1. Do the gauge control module self-diagnostic function procedure.
    • If the beeper sounds and the seat belt reminder light flashes, go to Step 13 .
    • If the beeper does not sound or the seat belt reminder light does not flash, replace the gauge control module (tach).
  1. Substitute a known-good gauge control module (tach) and recheck the system.
    • If the symptom is gone, the original gauge control module (tach) is faulty; replace it.
    • If the symptom is still present, the MICU is faulty; replace the under-dash fuse/relay box.