Gauge Control Module (Speedo) Input Test
  1. Turn the ignition switch OFF.
  1. Disconnect the gauge control module (speedo) 12P 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 5 .
  1. With the connector still disconnected, make these input tests at the connector.
    Cavity
    Wire
    Test condition
    Test: Desired result
    Possible cause if result is not obtained
    4
    BLK
    Under all conditions
    Check for continuity to ground: There should be continuity.
    • Poor ground (G503)
    • An open in the wire
    6
    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
    5
    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
    11
    BLU
    Ignition switch ON, turn signal switch in LEFT
    Check for voltage to ground: There should be battery voltage when the lights are flashing.
    • Faulty MICU
    • Faulty combination light switch
    • An open in the wire
    12
    BRN
    Ignition switch ON, turn signal switch in RIGHT
    Check for voltage to ground: There should be battery voltage when the lights are flashing.
    • Faulty MICU
    • Faulty combination light switch
    • An open in the wire
    7
    LT GRN
    Under all conditions (disconnect the gauge control module (tach) 36P connector)
    Check for continuity between the No. 7 terminal and the gauge control module (tach) 36P connector No. 20 terminal: There should be continuity.
    An open in the wire
    Attach to ground: There should be no continuity.
    A short to ground in the wire