INSPECTION PROCEDURE 7: Blower motor power supply system
TECHNICAL DESCRIPTION (COMMENT)
If the blower motor is not energized, the blower relay system is suspected.
TROUBLESHOOTING HINT
Malfunction of the blower relay
The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector
Malfunction of the ETACS-ECU
DIAGNOSIS
Required Special Tools:
MB991223: Harness Set
MB992006: Extra Fine Probe
STEP 1. Measure the voltage at blower relay connector.
(1)
Remove the relay, and measure at the ETACS-ECU side.
(2)
Voltage between power supply terminal and body ground
OK: System voltage
Is the check result normal?
Go to Step 3
.
Go to Step 2
.
STEP 2. Check of open circuit in blower relay power supply line between blower relay connector and fusible link (5).
note
Prior to the wiring harness inspection, check ETACS-ECU connector and repair if necessary.
Is the check result normal?
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction
).
Repair the connector(s) or wiring harness.
STEP 3. Check of open circuit in blower motor line between blower motor connector terminal and blower relay connector.
note
Prior to the wiring harness inspection, check ETACS-ECU connector and repair if necessary.
Is the check result normal?
Go to Step 4
.
Repair the connector(s) or wiring harness.
STEP 4. Retest the system.
Is the check result normal?
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction
).
Replace the ETACS-ECU.