5. High Beam Headlights Do Not Light Up, Bulbs Are OK

CIRCUIT OPERATION
The FRONT-ECU receives an ON signal from the high-beam side headlight relay, and supplies current to the headlights through dedicated fuse numbers 6 and 7

TECHNICAL DESCRIPTION (COMMENT)
If neither of the headlights does not light up, there may be a fault in the high-beam side headlight relay and the FRONT-ECU.

TROUBLESHOOTING HINTS
- Damaged harness wires or connectors
- Malfunction of the headlight relay (HIGH)
- Malfunction of the FRONT-ECU

DIAGNOSIS
Required Special Tool:
MB991223

STEP 1. Check headlight relay (HIGH) for continuity.
1. Remove the headlight relay (HIGH).







2. Check headlight relay (HIGH) for continuity.
If headlight relay (HIGH) is in good condition, go to Step 2.
If the headlight relay (HIGH) is faulty, replace it. Check that the malfunction is eliminated.




STEP 2. Check headlight relay connector A-07X for damage.
If headlight relay connector A-07X is damaged, repair or replace it. Refer to Harness Connector Inspection.
If harness connector A-07X is in good condition, go to Step 3.




STEP 3. Check the harness wires between headlight relay (HIGH) connector A-07X and the battery.
If the harness wires between headlight relay (HIGH) connector A-07X and the battery are damaged, repair them. Go to Step 4.




STEP 4. Check the headlight (HIGH-beam) power source.
1. Remove the headlights (both sides)
2. Measure at the harness side of headlight connectors A-27 and A-32
3. Measure voltage between terminal number 3 and the ground at the column switch HIGH position.
- The voltage should be approximately 12 volts (battery positive voltage).
If approximately 12 volts, go to Step 5.
If not approximately 12 volts, go to Step 6.




STEP 5. Check the harness wires between head light connectors A-27, A-32 and the body ground.
If the harness wires between headlight connectors A-27, A-32 and the body ground are damaged, repair them. Check the malfunction is eliminated.







STEP 6. Check the harness wires between headlight connector A-27 (LH), headlight connector A-32 (RH) and headlight relay (HIGH) A-27X.
If the harness wires between headlight connector A-27 (LH), headlight connector A-32 (RH) and headlight relay (HIGH) are damaged, repair them.
Check that the malfunction is eliminated.
If the harness wires are in good condition, go to Step 7.






NOTE: After inspecting intermediate connector C-05, inspect the wire. If intermediate connector C-05 is damaged, repair or replace it. Refer to Harness Connector Inspection.




STEP 7. Check connector A-09X at the FRONT-ECU for damage.
If connector A-09X is damaged, repair or replace it. Refer to Harness Connector Inspection.
If harness connector A-O9X is in good condition, go to Step 8.




STEP 8. Check the harness wires between FRONT-ECU connector A-09X and headlight relay (HIGH) A-07X.
If the harness wires between FRONT-ECU connector A-09X and headlight relay (HIGH) A-07X are damaged, repair them. Check that the malfunction is eliminated.
If the harness wires are in good condition, go to Step 9.

Step 9. Check symptoms.
Confirm that the headlights (HIGH-beam) are illuminated.