how to fix the rear AC not blowing in my Toyota Highlander Fourth Generation (2020-present)

Toyota Highlander Fourth Generation (2020-present)

Error Codes

2-4 hours

Time

medium

Difficulty

medium

Severity

3 min read

540 words

Problem Statement

Learn how to diagnose and fix the rear AC not blowing in a Toyota Highlander (2020-present). Step-by-step guide with tools and tips included.

Affected Component

HVAC

Estimated Time

2-4 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect the battery before working on electrical systems.
•Ensure the engine is cool before working on the HVAC system.

Symptoms

•No airflow from the rear AC vents
•Rear AC control panel lights not illuminating
•Unusual noises from the rear AC unit when activated
•Front AC functioning normally while rear AC is not
•Temperature difference between front and rear AC

Diagnostic Steps

1
Check the rear AC control settings to ensure they are properly set.
2
Inspect the rear AC fuses using the fuse box diagram.
3
Scan the vehicle's onboard diagnostics (OBD-II) for any error codes related to the HVAC system.
4
Examine the rear AC blower motor for any visible damage or obstructions.
5
Test the voltage at the rear AC blower motor connector using a multimeter.
6
Check for any blockages in the rear AC ducting.

Solution

💡 Expert Tip

For complex repairs like this, consider taking photos at each step. This helps if you need to reverse a step or consult with a mechanic. Also, keep all removed parts organized - you may need to reference them during reassembly.

Verification

After completing the repair, verify that the issue has been resolved:

✓Test the affected component to ensure it functions correctly
✓Check for any error codes or warning lights
✓Monitor the vehicle for a few days to ensure the issue does not recur

Prevention Tips

To prevent this issue from occurring again:

•Follow the manufacturer's recommended maintenance schedule
•Address warning signs early before they develop into major issues
•Use quality parts and fluids recommended for your vehicle
•Keep detailed records of all repairs and maintenance

Tools & Equipment Required

•Fuse puller or trim removal tool
•Multimeter
•Socket set
•Screwdrivers

Parts Required

•Rear AC blower motor (if found defective)
•Fuses (if blown)

Related Faults

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Diagnostic Steps

1
Check the rear AC control settings to ensure they are properly set.
2
Inspect the rear AC fuses using the fuse box diagram.
3
Scan the vehicle's onboard diagnostics (OBD-II) for any error codes related to the HVAC system.
4
Examine the rear AC blower motor for any visible damage or obstructions.
5
Test the voltage at the rear AC blower motor connector using a multimeter.
6
Check for any blockages in the rear AC ducting.

Solution

1. Preparation

Gather necessary tools and parts.
Disconnect the negative battery terminal to ensure safety.
Allow the vehicle to cool down if the engine has been running.

2. Inspect Fuses

Locate the fuse box (usually found under the dashboard or in the engine compartment).
Remove the cover and identify the rear AC fuse using the diagram.
Inspect the fuse for continuity; replace if blown.

3. Check Rear AC Control Panel

Remove the rear AC control panel using a trim removal tool.
Inspect wiring connections for corrosion or loose connections.
Reconnect any loose wires and ensure all connections are secure.

4. Test Rear AC Blower Motor

Access the rear HVAC unit by removing any necessary panels.
Disconnect the blower motor connector.
Use a multimeter to measure voltage while the rear AC is activated; voltage should be present if functioning correctly.
If no voltage is detected, further investigate wiring or control issues.

5. Replace Blower Motor (if faulty)

If the blower motor is determined to be defective, unbolt it from its mounting location.
Remove the old blower motor and replace it with a new one.
Reconnect the electrical connector and secure the new motor.

6. Reassemble Components

Reinstall any panels or components removed during the inspection.
Reconnect the negative battery terminal.
Test the rear AC functionality before finalizing the job.