Inspection Procedure N-7

Column switch: The ETACS-ECU does not receive any signal from windshield mist wiper switch, windshield intermittent wiper switch, windshield low-speed wiper switch, windshield high-speed wiper switch, rear wiper switch, windshield washer switch or rear washer switch.

NOTE: This troubleshooting procedure requires the use of scan tool MB991958 and SWS monitor kit MB991813. For details on how to use the SWS monitor, refer to "How to use SWS monitor."

Windshield Wiper And Washer Switch Input Circuit:

CIRCUIT OPERATION
The ETACS-ECU operates the following equipment or functions according to signal from the column switch (windshield wiper and washer switch):
- Windshield wiper and washer
- Rear wiper and washer

TECHNICAL DESCRIPTION (COMMENT)
If the signal is not normal, the equipment described in "CIRCUIT OPERATION" does network normally.

TROUBLESHOOTING HINTS
- The column switch (windshield wiper and washer switch) may be defective.
- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector.
- The ETACS-ECU may be defective.

DIAGNOSIS

Required Special Tools:
- MB991223: Harness Set
- MB992006: Extra Fine Probe
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: M.U.T.-III USB Cable
- MB991911: M.U.T.-III Main Harness B
- MB991813: SWS monitor kit
- MB991806: SWS monitor cartridge
- MB991812: SWS monitor harness (for column-ECU)
- MB991922: Probe harness

STEP 1. Use scan tool MB991502 to select "ECU COMM Check" on the SWS monitor display.
Check the column-ECU.

CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958. Connect special tool MB991911 before connecting special tool MB991812. Be sure to connect special tool MB991806 after turning on special tool MB991824.

1. Connect the special tool. Refer to "How to connect SWS monitor ".
2. Turn the ignition switch to the "LOCK" (OFF) position.
3. Operate scan tool MB991958 according to the procedure below to display "ECU COMM Check."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "ECU COMM Check."

4. Scan tool MB991958 should show "OK" on the "ECU COMM Check" menu for the "COLUMN ECU" menu.

Q: Is "OK" displayed on the "COLUMN ECU" menu?

YES: Go to Step 2.

NO: Refer to Inspection Procedure A-2 "Communication with the column switch (column-ECU) is not possible."

STEP 2. Check the windshield wiper and washer switch.
Remove the windshield wiper and washer switch. Then check continuity between the switch terminals.

Q: Are the windshield wiper and washer switch in good condition?

YES: Go to Step 3.

NO: Replace the column switch. If the equipment described in "CIRCUIT OPERATION" works normally, the input signal from the column switch (windshield wiper and washer switch) should be normal.

STEP 3. Check the 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 switch body in good condition?

YES: Go to Step 4.

NO: Replace the column switch. If the equipment described in "CIRCUIT OPERATION" works normally the input signal from the column switch (windshield wiper and washer switch) should be normal.

STEP 4. Replace the column switch.

1. Replace the column switch.
2. If the equipment described in "CIRCUIT OPERATION" works normally, the input signal from the column switch (windshield wiper and washer switch) should be normal.

Q: Does the column switch (windshield wiper and washer switch) send a normal signal to the ECU?

YES: No action is necessary and testing is complete.

NO: Replace the ETACS-ECU. If the equipment described in "CIRCUIT OPERATION" works normally, the input signal from the column switch (windshield wiper and washer switch) should be normal.