Control Unit Input Test
- Before testing, troubleshoot the multiplex control system (see TROUBLESHOOTING ).
- Remove the driver's dashboard lower cover (see DRIVER'S DASHBOARD LOWER COVER REMOVAL/INSTALLATION ).
- Disconnect the under-dash fuse/relay box connectors O, Q, X and Y.NOTE: All connectors are shown from wire side of female terminals.
- 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 look OK, go to step 5.
- With the connectors 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 6.REFERENCE TABLE
Cavity Wire Test condition Test: Desired result Possible cause if desired result is not obtained 07 GRN/RED Front ceiling light switch in middle position, interior light switch in door position*, all doors closed Attach to ground:
Front ceiling light should come on.- Blown No. 3 (7.5 A) fuse in the under-hood fuse/relay box
- Blown bulb
- Faulty front ceiling light
- An open in the wire
07 GRN/RED Front ceiling light switch in middle position, all doors closed Attach to ground:
Front ceiling light should come on.- Blown No. 3 (7.5 A) fuse in the under-hood fuse/relay box
- Blown bulb
- Faulty front ceiling light
- An open in the wire
X8 WHT/BLK Under all conditions Attach to ground:
Ignition key light should come on.- Blown No. 3 (7.5 A) fuse in the under-hood fuse/relay box
- Faulty ignition key light (LED)
- An open in the wire
- Reconnect the connectors to the under-dash fuse/relay box, and make these input tests at the appropriate connectors on the under-dash fuse/relay box.
- If any test indicates a problem, find and correct the cause, then recheck the system.
- If all the input tests prove OK, the multiplex control unit must be faulty, replace the under-dash fuse/relay box assembly.REFERENCE TABLE
Cavity Wire Test condition Test: Desired result Possible cause if desired result is not obtained Q3 GRN Driver's door or left rear door open Measure voltage to ground:
There should be less than 0.5 V.- Faulty driver's door switch
- Faulty left rear door switch
- An open in the wire
Driver's door and left rear door closed Measure voltage to ground: There should be battery voltage. - Faulty driver's door switch
- Faulty left rear door switch
- Short to ground in the wire
Q4 GRY/BLK Front passenger's door or right rear door open Measure voltage to ground:
There should be less than 0.5 V.- Faulty front passenger's door switch
- Faulty right rear door switch
- An open in the wire
Front passenger's door and right rear door closed Measure voltage to ground:
There should be battery voltage.- Faulty front passenger's door switch
- Faulty right rear door switch
- Short to ground in the wire
X5 RED/WHT Ignition key inserted into the ignition switch Measure voltage to ground:
There should be less than 0.5 V.- Poor ground (G401)
- Faulty ignition key switch
- An open in the wire
Ignition key removed from the ignition switch Measure voltage to ground:
There should be battery voltage.- Faulty ignition key switch
- Short to ground in the wire
Y8 YEL/RED Driver's door lock knob switch locked Measure voltage to ground:
There should be less than 0.5 V.- Poor ground (G501)
- Faulty driver's door lock knob switch
- An open in the wire
Driver's door lock knob switch unlocked Measure voltage to ground: There should be battery voltage. - Faulty driver's door lock knob switch
- Short to ground in the wire
Y7 WHT/BLK Driver's door lock knob switch locked Measure voltage to ground:
There should be battery voltage.- Faulty driver's door lock knob switch
- Short to ground in the wire
Driver's door lock knob switch unlocked Measure voltage to ground:
There should be less than 0.5 V.- Poor ground (G501)
- Faulty driver's door lock knob switch
- Short to ground in the wire