Inspection Procedure L-7

Column Switch: ETACS-ECU does not Receive Any Signal from the Windshield Intermittent Wiper Interval Adjusting Knob

Windshield Intermittent Wiper Interval Adjusting Knob Input Circuit:

CIRCUIT OPERATION
The ETACS-ECU calculates the windshield intermittent wiper interval according to the position of the windshield intermittent wiper interval adjusting knob, which is incorporated in column switch (windshield wiper and washer switch).

TECHNICAL DESCRIPTION (COMMENT)
If the windshield intermittent wiper interval can not be adjusted, the column switch or the ETACS-ECU may be defective.

TROUBLESHOOTING HINTS
- Malfunction of the column switch (windshield wiper and washer switch)
- Malfunction of the ETACS-ECU
- Damaged harness wires or connectors

DIAGNOSIS

Required Special Tools:
- MB991223: Test Harness Set
- MB991502: Scan Tool (MUT-II)
- MB991862: SWS monitor kit




STEP 1. Check the windshield intermittent wiper interval adjusting knob.

1. Remove the windshield wiper and washer switch, and check at the switch side.
2. Measure the resistance value between terminals 3 and 6. The measured resistance should change smoothly from approximately 0 Ohm ("FAST" position) to 1 Kohm ("SLOW position).

Q: Is the windshield intermittent wiper interval adjusting knob in good condition?

YES: Go to Step 2.

NO: Replace the column switch (windshield wiper and washer switch). If the wiper interval can be adjusted normally, it indicates that the windshield intermittent wiper interval adjusting knob should send a signal to the ECU.







STEP 2. Check the column switch body.

Remove the turn-signal light and lighting switch and windshield wiper and washer switch. Then check continuity between the switch body terminals.

Q: Is the column switch body in good condition?

YES: Go to Step 3.

NO: Replace the column switch body. If the wiper interval can be adjusted normally, it indicates that the windshield intermittent wiper interval adjusting knob should send a signal to the ECU.







STEP 3. Check column switch connector C-206 and ETACS-ECU connector C-228 for damage.

Q: Are column switch connector C-206 and ETACS-ECU connector C-228 in good condition?

YES: Go to Step 4.

NO: Repair or replace the connector. Refer to Harness Connector Inspection. If the wiper interval can be adjusted normally, it indicates that the windshield intermittent wiper interval adjusting knob should send a signal to the ECU.







STEP 4. Check the wiring harness between column switch connector C-206 and ETACS-ECU connector C-228.

Q: Is the wiring harness between column switch connector C-206 and ETACS-ECU connector C-228 in good condition?

YES: Go to 5.

NO: Repair the wiring harness. If the wiper interval can be adjusted normally, it indicates that the windshield intermittent wiper interval adjusting knob should send a signal to the ECU.

STEP 5. Replace the ECU.

1. Replace the ETACS-ECU.
2. If the wiper interval can be adjusted normally, it indicates that the windshield intermittent wiper interval adjusting knob should send a signal to the ECU.

Q: Can input signal be confirmed when the windshield intermittent wiper interval adjusting knob is operated?

YES: No action to be taken.

NO: Replace the column switch (windshield wiper and washer switch). If the wiper interval can be adjusted normally, it indicates that the windshield intermittent wiper interval adjusting knob should send a signal to the ECU.