HFT Control Unit Input Test/Replacement
  1. Disconnect the 28P connector (A) from the Hands Free Telephone control unit (B).
  1. Inspect the connector and socket terminals for a good pinfit 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 look OK, go to Step 4 .
  1. Reconnect the connector, and 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 5 .
    Cavity
    Wire
    Test condition
    Test: Desired result
    Possible cause if result is not obtained
    1
    BLK
    Under all conditions
    Measure the voltage to ground: There should be less than 0.5 V.
    • Poor ground (G401)
    • An open in the wire
    15
    WHT
    Under all conditions
    Measure the voltage to ground: There should be battery voltage.
    • Blown No. 15 (10 A) fuse in the under-hood fuse/relay box
    • An open in the wire
    16
    PUR
    Ignition switch in ACC (I) or ON (II)
    Measure the voltage to ground: There should be battery voltage.
    • Blown No. 18 (7.5 A) fuse in the driver's under-dash fuse/relay box
    • An open in the wire

  1. Disconnect the 28P connector again, and make this input test at the connector.
    • If the test indicates a problem, find and correct the cause, then recheck the system.
    • If the input test proves OK, the HandsFreeLink control unit is faulty, replace it.
    Cavity
    Wire
    Test condition
    Test: Desired result
    Possible cause if result is not obtained
    17
    BLU
    Under all conditions
    Check for continuity between No. 17 terminal and the passenger's under-dash fuse/relay box connector D (28P) No. 8 terminal: There should be continuity.
    An open in the wire
    Passenger's under-dash fuse/relay box connector D (28P) disconnected
    Check for continuity to ground: There should be no continuity.
    Short to ground
    18
    PNK
    Under all conditions
    Check for continuity between No. 18 terminal and the passenger's under-dash fuse/relay box connector D (28P) No. 7 terminal: There should be continuity.
    An open in the wire
    Passenger's under-dash fuse/relay box connector D (28P) disconnected
    Check for continuity to ground: There should be no continuity.
    Short to ground