Inspection Procedure B-4: One of the turn-signal lamps does not illuminate.


caution Whenever the ECU is replaced, ensure that the input and output signal circuits are normal.

COMMENTS ON TROUBLE SYMPTOM
If one of the turn-signal lamps does not illuminate, the wiring harness connector(s) or the bulb may be defective.

PROBABLE CAUSES

  • Defective turn-signal lamp bulb
  • Malfunction of side turn-signal lamp assembly
  • Damaged harness wires and connectors

DIAGNOSIS PROCEDURE

STEP 1. Confirm which turn-signal lamp is defective.

Q. Which turn-signal lamp fails to illuminate correctly?
YES (All of the turn-signal lamps illuminate normally) : The procedure is complete.
NO (Only the front or rear turn-signal lamps does not illuminate normally) : Refer to ETACS diagnosis code chart.
NO (Only the side turn-signal lamps does not illuminate normally) : Go to Step 2.

STEP 2. Resistance measurement at the side turn-signal lamp connector.
(1)Disconnect the connector, and measure at the wiring harness side.
(2)Measure the resistance between the defective lamp connector terminal and body earth.

  • Measure the resistance between the door mirror assembly (LH) connector (earth terminal) and the body earth.
  • Measure the resistance between the door mirror assembly (RH) connector (earth terminal) and the body earth.
OK: Continuity exists (2 Ω or less)

Q. Is the check result normal?
Go to Step 4.
Go to Step 3.

STEP 3. Check of open circuit in earth line between door mirror assembly and body earth.

Q. Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).
Repair the connector(s) or wiring harness.

STEP 4. Check of open circuit in TURN LH or TURN RH line between door mirror assembly connector and ETACS-ECU connector.

Q. Is the check result normal?
Go to Step 5.
Repair the connector(s) or wiring harness.

STEP 5. Retest the system.
Check that the side turn-signal lamp flashes normally when the turn-signal switch is operated.

Q. Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).
Replace the side turn-signal lamp assembly (Refer to GROUP 51 - Door Mirror ).