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Inspection Procedure 5: One of the headlight(s) does not illuminate.
 
 
 
 
TECHNICAL DESCRIPTION (COMMENT)
When one of the headlights does not illuminate, the wiring harness, connector(s), the bulb, or the LED may have a problem, or the fuse may be burned out.
 
 
TROUBLESHOOTING HINTS
  • The headlight bulbs or LED may be defective
  • The headlight assembly may be defective
  • The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector
 
 
DIAGNOSIS
Required Special Tools:
  • MB992006: Extra fine probe
  • MB991223: Harness set
STEP 1. Bulb check.
Check the bulb(s) or LED of headlight that does not illuminate.
noteIf LED-type low-beam headlights do not illuminate, their LED cannot be inspected. In this case, assume the LED to be normal and proceed with steps.
Is the check result normal?
Go to Step 2.
Replace the bulb(s) of the light that does not illuminate.
 
STEP 2. Resistance measurement at the headlight assembly (LH) or (RH) connector (ground terminals).
(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 ground.
  • Measure the resistance between the headlight assembly (LH) or (RH) connector (ground terminals) and ground.
OK: The resistance should be 2 ohms or less
Is the check result normal?
Go to Step 4.
Go to Step 3.
 
STEP 3. Check of open circuit in ground lines between the headlight assembly (LH) or (RH) connector and ground.
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 power supply lines between the headlight assembly (LH) or (RH) connector and headlight relay (LOW) or (HIGH) connector.
Is the check result normal?
Replace the headlight assembly that does not illuminate.
Repair the connector(s) or wiring harness.