Inspection Procedure 2: One of the taillights does not illuminate: Diagnosis

Required Special Tools:

MB992006: Extra fine probe
MB991223: Harness set

STEP 1. Bulb check.
Check the bulb(s) of the light that does not illuminate.

Q: Is the check result normal?

YES: Go to Step 2.

NO: Replace the bulb(s) of the light that does not illuminate.
STEP 2. Check rear combination light connector D-19 (taillight/side marker light: LH) or D-13 (taillight/side marker light: RH) for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Q: Is rear combination light connector D-19 (taillight/side marker light: LH) or D-13 (taillight/side marker light: RH) in good condition?

YES: Go to Step 3.

NO: Repair or replace the damaged component(s). Refer to HARNESS CONNECTOR INSPECTION .
STEP 3. Resistance measurement at rear combination light connector D-19 (taillight/side marker light: LH) or D-13 (taillight/side marker light: RH).
1. Disconnect the connector, and measure at the wiring harness side.
2. Measure the resistance between the connector of light which does not illuminate and body ground.
  - Measure the resistance between rear combination light (taillight/side marker light: LH) connector D-19 (terminal 4) and body ground.
    
    Fig 1: Measuring Resistance Between Rear Combination Light (Taillight/Side Marker Light LH) Connector D-19 (Terminal 4) And Body Ground
    Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    
    Fig 2: Measuring Resistance Between Rear Combination Light (Taillight/Side Marker Light RH) Connector D-13 (Terminal 4) And Body Ground
    Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
  - Measure the resistance between rear combination light (taillight/side marker light: RH) connector D-13 (terminal 4) and body ground.
    OK: The measured value should be continuity exists (2 ohms or less).
Q: Does the measured resistance value correspond with this range?

YES: Go to Step 5.

NO: Go to Step 4.
STEP 4. Check the wiring harness between rear combination light connectors D-19 (taillight/side marker light: LH) (terminal 4) or D-13 (taillight/side marker light: RH) (terminal 4) and ground.
Q: Is the wiring harness between rear combination light connectors D-19 (taillight/side marker light: LH) (terminal 4) or D-13 (taillight/side marker light: RH) (terminal 4) and ground in good condition?

YES: Go to Step 7.

NO: The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary.
STEP 5. Check ETACS-ECU connectors C-413 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Q: Is ETACS-ECU connectors C-413 in good condition?

YES: Go to Step 6.

NO: Repair or replace the damaged component(s). Refer to HARNESS CONNECTOR INSPECTION .
STEP 6. Check the wiring harness between rear combination light connector and ETACS-ECU connector.
Check the power supply line for open circuit.
- Check the wiring harness between rear combination light (taillight/side marker light: LH) connector D-19 (terminal 2) and ETACS-ECU connector C-413 (terminal 10). <LH>
- Check the wiring harness between rear combination light (taillight/side marker light: RH) connector D-13 (terminal 2) and ETACS-ECU connector C-413 (terminal 13). <RH>
Q: Is the wiring harness between rear combination light connector and ETACS-ECU connector in good condition?

YES: Go to Step 7.

NO: The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary.
STEP 7. Retest the system.
Check that the taillight illuminates normally.

Q: Does the taillight work normally?

YES: The trouble can be an intermittent malfunction (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTIONS ).

NO: Replace the defective rear combination light unit.