12. Turn Signals Do Not Work With Switch, Bulbs OK
CIRCUIT OPERATION
If the ETACS-ECU receives a signal from the turn-signal switch, the flasher timer circuit (which is incorporated in the ETACS-ECU) makes the front and rear combination lights flash.
TECHNICAL DESCRIPTION (COMMENT)
The ETACS-ECU receives a signal from the turn-signal switch via the SWS. The SWS sends all signals of the column switch. Therefore, if the switches other than the turn-signal switch work correctly, the SWS is normal.
TROUBLESHOOTING HINTS
- Malfunction of the ETACS-ECU
- Malfunction of the column switch
- Damaged harness wire or connector
DIAGNOSIS
Required Special Tools:
MB991223: Harness set
MB991502: Scan Tool (MUT-II)
MB991529: Diagnostic Trouble Code Check Harness
CAUTION: To prevent damage to scan tool MB991502, make sure that the ignition switch is "OFF" before connecting or disconnecting the scan tool.
STEP 1. Check the input signal from the turn signal switch, using either the scan tool or a voltmeter.
- Using scan tool MB991502
1. Connect Scan Tool MB991502 to the data link connector.
2. Check that the tone alarm of the scan tool sounds when the turn signal switch is on.
If the tone alarm of the scan tool does not sound, input signal from the turn signal switch is not normal. Go to Step 2.
If the tone alarm of the scan tool sounds, input signal from the turn signal switch is normal. Go to Step 8.
- Using a voltmeter
1. Use special tool MB991529 to connect a voltmeter between ground terminal 4 or 5 and ETACS-ECU terminal 9 of the data link connector.
2. If a voltmeter indicator deflects once when the turn signal switch is on, the ETACS-ECU input signal for that turn signal switch is normal.
If the input signal of the turn signal switch is not normal, go to Step 2.
If the input signal of the turn signal switch is normal , go to Step 8.
STEP 2. Check the ETACS-ECU power supply (IG1)
1. Remove the instrument panel side cover.
2. Disconnect ETACS-ECU connector C-86.
3. Turn the ignition switch "ON."
4. Measure voltage between ETACS-ECU connector C-86 terminal number 11 and ground.
- Voltage should be approximately 12 volts (battery positive voltage).
If approximately 12 volts, repair the ETACS-ECU. Check that the malfunction is eliminated.
If not approximately 12 volts, go to Step 3.
STEP 3. CHECK ETACS-ECU connector C-86 for damage.
If harness connector C-86 is damaged, repair or replace it.
Refer to Harness Connector Inspection.
If harness connector C-86 is in good condition, go to Step 4.
STEP 4. Check the harness wires between ETACS-ECU connector C-86 and the ignition switch.
If any harness wires between ETACS-ECU C-86 and the ignition switch are damaged, repair them.
If the harness wires are in good condition, go to Step 5.
NOTE: After inspecting junction block connector C73, inspect the wire. If junction block connector C-73 is damaged, repair or replace it Refer to Harness Connector Inspection.
STEP 5. Check the ETACS-ECU power supply (battery).
1. Measure voltage between ETACS-ECU connector C-86 terminal number 2 and ground.
- Voltage should be approximately 12 volts (battery positive voltage).
2. Measure voltage between ETACS-ECU connector C-86 terminal number 18 and ground.
- Voltage should be approximately 12 volts (battery positive voltage).
If approximately 12 volts, repair the ETACS-ECU. Check that the malfunction is eliminated.
If not approximately 12 volts, go to Step 6.
STEP 6. Check the harness wires between ETACS-ECU connector C-86 and battery.
If any harness wires between ETACS-ECU C-86 and battery
are damaged, repair them.
If the harness wires are in good condition, go to Step 7.
NOTE: After inspecting intermediate connector C-66 and junction block connectors C-78 and C-84, inspect the wire. If intermediate connector C-66 and junction block connectors C-78 and C-84 are damaged, repair or replace them. Refer to Harness Connector Inspection.
STEP 7. Check the harness wire between ETACS-ECU C-86 and body ground.
If the harness wires between ETACS-ECU connector C-86 and body ground are damaged, repair them. Check that the malfunction is eliminated, and then go to step 8.
NOTE: After inspecting junction block connector C-73, inspect the wire. If junction block connector C-73 is damaged, repair or replace it. Refer to Harness Connector Inspection.
STEP 8. Check the column switch power supply.
1. Remove the column covers, lower and upper.
2. Disconnect column switch connector C-60.
3. Turn the ignition switch "ON."
4. Measure voltage between column switch connector C-60 terminal number 9 and ground.
- Voltage should be approximately 12 volts (battery positive voltage).
If approximately 12 volts, repair the column switch. Check that the malfunction is eliminated.
If not approximately 12 volts, go to Step 9.
STEP 9. Check column switch connector C-60 for damage.
If harness connector C-60 is damaged, repair it. Refer to Connector Harness Inspection.
If harness connector C-60 is in good condition, go to Step 10.
STEP 10. Check the harness wires between column switch C40 and ignition switch.
If any harness wires between column switch C-60 and the ignition switch are damaged, repair them. Refer to Harness Connector Inspection.
If harness wires are in good condition, go to Step 11.
NOTE: After inspecting junction block connectors C-73 and C-78, inspect the wire. If junction block connectors C-73 and C-78 are damaged, repair or replace them. Refer to Harness Connector Inspection.
STEP 11 Check the harness wires between column switch C-60 and ETACS-ECU C-82.
If any harness wires between column switch C-60 and ETACS-ECU C-82 are damaged, repair it. Refer to Harness Connector Inspection.
It harness wires are in good condition, repair the column switch and go to Step 12.
STEP 12. Check symptoms.
Confirm that the turn signal switch operates normally.