INSPECTION PROCEDURE L-3: The high-beam headlamps do not illuminate normally.


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


COMMENTS ON TROUBLE SYMPTOM
If the high-beam headlamps do not illuminate, the dimmer switch input circuit or the front-ECU may be defective.

POSSIBLE CAUSES

  • Malfunction of the column switch
  • Malfunction of the front-ECU
  • Damaged harness wires and connectors

DIAGNOSTIC PROCEDURE

Step 1. Check that the headlamps operate.
Check that the low-beam headlamps illuminate and extinguish normally.

Q. Is the check result normal?
Go to Step 2.
Refer to inspection procedure L-2 "The low-beam headlamps do not illuminate normally ."

Step 2. Pulse check
Check the input signal from the dimmer switch.
System switch
 Check condition
Dimmer switch
 When the dimmer switch is turned from off to on
OK: The M.U.T.-III sounds or the voltmeter needle fluctuates.

Q. Is the check result normal?
Go to Step 3.
Refer to inspection procedure P-6 "The column switch (lighting and turn-signal lamp switch) signal is not received ."

Step 3. Retest the system.
Check that the high-beam headlamps illuminate normally.

Q. Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
Replace the front-ECU.