INSPECTION PROCEDURE K-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

DIAGNOSIS PROCEDURE

Step 1. Check that the headlamps operate.

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

Q: Is the check result normal?

YES: Go to Step 2

.
NO: Refer to inspection procedure K-2 "The low-beam headlamps do not illuminate normally

Step 2. Pulse check

Check the input signals below, which are related to the high-beam headlamps.

System switch	Check conditions
Ignition switch (IG1)	When turned from ACC to ON
Dimmer switch	When the dimmer switch is turned from off to on

OK: The MUT-II/III sounds or the voltmeter needle fluctuates.

Q: Are the check result normal?

All the signals are received normally.: Go to Step 3

.
The ignition switch (IG1) signal is not received.: Refer to inspection procedure P-2 "The ignition switch (IG1) signal is not received"

.
The dimmer switch signal is not received.: Refer to inspection procedure P-5 "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?

YES: The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction

).
NO: Replace the front-ECU.