how to fix the AC not cooling in my Toyota Highlander Third Generation (2014-2019)

Toyota Highlander Third Generation (2014-2019)

Error Codes

2-4 hours

Time

medium

Difficulty

medium

Severity

4 min read

638 words

Problem Statement

Learn how to diagnose and fix AC not cooling in Toyota Highlander 2014-2019. Step-by-step guide with symptoms, diagnostic steps, and repair instructions.

Affected Component

HVAC

Estimated Time

2-4 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect the battery before working on electrical systems.
•Allow the AC system to depressurize before handling refrigerants.

Symptoms

•Check engine light illuminated
•Weak or no airflow from AC vents
•Unpleasant odors emanating from the AC system
•AC compressor not engaging
•Frequent cycling of the AC compressor
•Ice buildup on the evaporator or refrigerant lines

Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to identify any related issues within the engine or AC system.
2
Check the refrigerant level using a manifold gauge set to determine if it is low or overfilled.
3
Inspect the AC compressor visually for signs of damage or wear, such as cracks or leaks.
4
Test the AC system operation with the engine running to ensure the compressor engages and check for abnormal noises.
5
Inspect the cabin air filter for blockages that could restrict airflow.
6
Examine the AC relay and fuse to ensure they are functioning properly.

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

•OBD-II scanner
•Manifold gauge set
•Socket set
•Screwdriver set
•Refrigerant canister (R-134a)
•Torque wrench

Parts Required

•R-134a refrigerant
•Cabin air filter
•AC compressor (if needed)

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Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to identify any related issues within the engine or AC system.
2
Check the refrigerant level using a manifold gauge set to determine if it is low or overfilled.
3
Inspect the AC compressor visually for signs of damage or wear, such as cracks or leaks.
4
Test the AC system operation with the engine running to ensure the compressor engages and check for abnormal noises.
5
Inspect the cabin air filter for blockages that could restrict airflow.
6
Examine the AC relay and fuse to ensure they are functioning properly.

Solution

1. Preparation

Gather tools and parts needed for the repair.
Disconnect the vehicle battery to ensure safety while working on electrical components.

2. Recharge the AC System

1. Connect the manifold gauge set to the AC service ports (low and high side).
2. If refrigerant is low, use a refrigerant canister to add R-134a refrigerant until the appropriate pressure is reached (typically 30-40 psi on the low side and 200-250 psi on the high side).
3. Monitor the gauge readings closely while adding refrigerant to avoid overfilling.

3. Replace Cabin Air Filter

1. Locate the cabin air filter compartment, usually behind the glove box.
2. Remove the glove box by detaching the stops and hinges.
3. Remove the old cabin air filter and clean any debris from the compartment.
4. Install the new cabin air filter, ensuring it is oriented correctly according to airflow direction.

4. Inspect and Replace AC Compressor (if necessary)

1. Remove any accessories or components obstructing access to the AC compressor.
2. Disconnect the electrical connector from the compressor.
3. Unbolt the compressor from its mounting bracket using the appropriate socket size.
4. Remove the refrigerant lines connected to the compressor, ensuring to recover refrigerant properly.
5. Install the new compressor by reversing the removal steps, ensuring all connections are tight.
6. Replace any O-rings or seals that were disturbed during the replacement.

5. Test AC System

1. Reconnect the vehicle battery.
2. Start the engine and turn the AC on to the maximum setting.
3. Use the manifold gauge set to check for proper system pressures; observe that the compressor engages and the system cools effectively.