why is my Toyota Highlander Third Generation (2014-2019) AC not blowing cold air?

Toyota Highlander Third Generation (2014-2019)

Error Codes

2-4 hours

Time

medium

Difficulty

medium

Severity

4 min read

621 words

Problem Statement

Learn how to diagnose and fix AC not blowing cold air in Toyota Highlander (2014-2019). Step-by-step guide with diagnostic procedures 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.
•Wear safety goggles and gloves when handling refrigerants.

Symptoms

•AC system blowing warm air
•Increased humidity inside the vehicle
•AC compressor not engaging
•Unusual noises from the AC compressor
•AC system cycling on and off frequently
•Dashboard AC controls not functioning properly

Diagnostic Steps

1
Check the AC settings to ensure it is set to the coldest temperature and the highest fan speed.
2
Inspect the AC compressor visually to see if it is engaging when the AC is turned on.
3
Use an OBD-II scanner to check for any error codes related to the AC system.
4
Examine the refrigerant levels using a manifold gauge set to determine if they are low.
5
Inspect the fuses and relays associated with the AC system to ensure they are functioning.
6
Look for any signs of leaks in the AC system components (hoses, connections, condenser).

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
•Torque wrench

Parts Required

•Refrigerant (R-134a)
•AC compressor (if replacing)
•Cabin air filter (if replacing)

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Diagnostic Steps

1
Check the AC settings to ensure it is set to the coldest temperature and the highest fan speed.
2
Inspect the AC compressor visually to see if it is engaging when the AC is turned on.
3
Use an OBD-II scanner to check for any error codes related to the AC system.
4
Examine the refrigerant levels using a manifold gauge set to determine if they are low.
5
Inspect the fuses and relays associated with the AC system to ensure they are functioning.
6
Look for any signs of leaks in the AC system components (hoses, connections, condenser).

Solution

1. Preparation

Gather necessary tools and parts.
Ensure the vehicle is parked on a level surface and the engine is turned off.
Disconnect the battery before working on electrical components.

2. Recharge Refrigerant

Tools Required: Manifold gauge set, refrigerant (R-134a), safety goggles, gloves.
Instructions:
1. Connect the low-pressure gauge of the manifold set to the AC service port.
2. Start the engine and turn the AC to max cool.
3. Check the pressure reading; if low, proceed to add refrigerant.
4. Attach a can of refrigerant to the manifold gauge set and open the valve slowly to allow refrigerant to enter the system.
5. Monitor the pressure gauge to ensure it reaches the manufacturer’s specified range (typically 25-45 psi on the low side).

3. Replace AC Compressor (if necessary)

Tools Required: Socket set, torque wrench, AC compressor replacement, new O-rings.
Instructions:
1. Disconnect the battery.
2. Remove the serpentine belt from the AC compressor.
3. Disconnect electrical connectors and refrigerant lines from the compressor.
4. Unbolt the compressor from its mounting bracket and remove it from the engine bay.
5. Install the new compressor, ensuring to use new O-rings for the refrigerant lines and torque to manufacturer specifications.
6. Reconnect all electrical connections and refrigerant lines.

4. Check and Replace Cabin Air Filter (if necessary)

Tools Required: None.
Instructions:
1. Locate the cabin air filter compartment (usually behind the glove box).
2. Remove the old filter and inspect for dirt or blockages.
3. Install a new cabin air filter according to the manufacturer’s specifications.