What should I do if the rear air conditioning is not blowing cold air in my 2020 Toyota Highlander?

Toyota Highlander Fourth Generation (2020-present)

Error Codes

1-2 hours

Time

medium

Difficulty

medium

Severity

4 min read

677 words

Problem Statement

Learn how to diagnose and repair the rear air conditioning system in your 2020 Toyota Highlander if it's not blowing cold air. Follow our step-by-step guide.

Affected Component

Rear Air Conditioning System

Estimated Time

1-2 hours

Symptoms

•Rear AC vents are blowing warm air.
•Front AC may be functioning properly while the rear is not.
•Possible unusual noises from the rear AC unit.

Diagnostic Steps

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

•Digital multimeter
•AC manifold gauge set
•Screwdrivers (flathead and Phillips)
•Pliers
•Replacement cabin air filter
•Refrigerant (if low)
•Vacuum pump (if refrigerant needs to be recharged)

Related Faults

Share this solution

Comments

No comments yet

Be the first to share your thoughts

Back to Generation

Solution

If the rear air conditioning in your 2020 Toyota Highlander is not blowing cold air, follow these detailed steps to diagnose and repair the issue.

Tools Required

Digital multimeter
AC manifold gauge set
Screwdrivers (flathead and Phillips)
Pliers
Replacement cabin air filter
Refrigerant (if low)
Vacuum pump (if refrigerant needs to be recharged)

Repair Instructions

Step 1: Check the Temperature Settings

Turn on the engine and set the front and rear AC to the lowest temperature setting.
Adjust the rear settings using the rear climate control panel.

Step 2: Inspect the Rear AC Controls

Ensure that the rear AC control panel illuminates and responds to inputs. If not, the panel may be faulty.

Step 3: Examine the Refrigerant Level

Attach the AC manifold gauge set to the low and high-pressure ports located near the AC compressor.
Check the pressure readings:
- Low pressure should be between 25-45 psi (this can vary slightly based on ambient temperature).
- High pressure should be around 200-250 psi.
If the low side reading is below 25 psi, you likely have a refrigerant leak.

Step 4: Check the Cabin Air Filter

Open the glove compartment and remove it to access the cabin air filter housing.
Remove the old filter and inspect it for dirt and debris.
Install a new cabin air filter if the old one is clogged.

Step 5: Test the Blower Motor

If the blower motor is not operational, check for power using a multimeter.
Disconnect the blower motor connector and test for voltage while the AC is on.
If there is no power, check the associated fuses and wiring.
If power is present but the motor does not run, replace the blower motor.

Step 6: Inspect the AC System Components

If no issues are found in the previous steps, further investigate the rear evaporator or expansion valve.
Remove the rear AC unit cover (if applicable) to access the evaporator.
Look for ice buildup or blockage and clear any obstructions.
If necessary, replace the expansion valve.

Final Steps

Refrigerant Recharge: If you found low refrigerant, evacuate the system using a vacuum pump and recharge it according to the manufacturer's specifications.
Test the System: After repairs, run the rear AC with the engine on for approximately 10-15 minutes to check for proper cooling.
Monitor Performance: Ensure both front and rear systems are functioning correctly over the next few days.

By following these steps, you should be able to diagnose and fix the issue with the rear air conditioning in your 2020 Toyota Highlander. If problems persist after these steps, consider consulting a professional technician for further diagnosis.