Inspection Procedure 2

Inspection Procedure 2: Light intensity cannot be adjusted using sunshade illumination changeover switch.

CAUTION:
Whenever the ECU is replaced, ensure that the power supply circuit, the ground circuit and the communication circuit are normal.














TECHNICAL DESCRIPTION (COMMENT)

While the sunshade illumination is ON, if the sunshade illumination brightness does not change even when the sunshade illumination changeover switch is pressed, the sunshade illumination changeover switch, ETACS-ECU, wiring harness, or connector may have a problem.

TROUBLESHOOTING HINTS

- Malfunction of the sunshade illumination changeover switch
- Malfunction of the ETACS-ECU
- Damaged harness wires and connectors

DIAGNOSIS

Required Special Tools:

- MB991223: Harness Set
- MB992006: Extra Fine Probe

STEP 1. Check ETACS-ECU connector C-411, sunshade illumination changeover switch connector E-12 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q. Is ETACS-ECU connector C-411, sunshade illumination changeover switch connector E-12 in good condition?

YES Go to Step 2.
NO Repair or replace the damaged component(s). Harness Connector Inspection.
STEP 2. Check of sunshade illumination changeover switch

Check the sunshade illumination changeover switch. Refer to Component Tests and General Diagnostics.

Q. Is the check result normal?

YES Go to Step 3.
NO Replace the sunshade illumination changeover switch.
STEP 3. Resistance measurement at the E-12 sunshade illumination changeover switch connector

(1)Disconnect the connector, and measure at the wiring harness side.





(2)Measure the resistance between the E-12 sunshade illumination changeover switch connector terminal No. 1 and the body earth.
OK: The measured value should be continuity exists (2 ohms or less).

Q. Is the measured resistance 2 ohms or less?

YES Go to Step 5.

NO Go to Step 4.

STEP 4. Check the wiring harness between the sunshade illumination changeover switch connector E-12 terminal No. 1 and the ground

- Check the ground wires for open circuit.

Q. Is the wiring harness between sunshade illumination changeover switch connector E-12 terminal No. 1 and ground in good condition?

YES The trouble can be an intermittent malfunction How to Cope With Intermittent Malfunctions).
NO The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary.
STEP 5. Check the wiring harness between ETACS-ECU connector C-411 terminal No. 17 and sunshade illumination changeover switch connector E-12 terminal No. 2

NOTE:
Also check intermediate connector C-226 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-226 is damaged, repair or replace the connector as described in Harness Connector Inspection Harness Connector Inspection.

- Check the power supply lines for open and short circuit.

Q. Is the check result normal?

YES Go to Step 6.
NO The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary.
STEP 6. Retest the system

While the sunshade illumination is ON, check that the sunshade illumination brightness changes when the sunshade illumination changeover switch is pressed.

Q. Is the check result normal?

YES The trouble can be an intermittent malfunction How to Cope With Intermittent Malfunctions).
NO Replace the ETACS-ECU.