my Toyota Highlander Third Generation (2014-2019) AC is blowing warm air what should I check

Toyota Highlander Third Generation (2014-2019)

Error Codes

2-4 hours

Time

medium

Difficulty

medium

Severity

3 min read

587 words

Problem Statement

Learn how to diagnose and fix AC blowing warm 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.
•Allow the engine to cool before opening the hood and working on AC components.

Symptoms

•AC system blowing warm air
•Loud noises from the AC compressor
•AC compressor not engaging
•Foul odor from vents
•Reduced airflow from vents
•Dashboard warning lights illuminated

Diagnostic Steps

1
Check the AC settings to ensure the system is set to 'Max AC' and the temperature is set to the lowest setting.
2
Inspect the AC compressor for engagement when the system is turned on.
3
Use an OBD-II scanner to check for any stored error codes related to the AC system.
4
Check the refrigerant level using a manifold gauge set to determine if it is low.
5
Inspect for visible leaks in the AC hoses and components.
6
Test the AC blend door actuator for proper operation.

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
•Refrigerant canister
•Socket set
•Torque wrench
•AC compressor removal tool
•Multimeter

Parts Required

•Refrigerant
•AC compressor (if defective)
•AC drive belt (if worn)

Related Faults

Share this solution

Comments

No comments yet

Be the first to share your thoughts

Back to Generation

Diagnostic Steps

1
Check the AC settings to ensure the system is set to 'Max AC' and the temperature is set to the lowest setting.
2
Inspect the AC compressor for engagement when the system is turned on.
3
Use an OBD-II scanner to check for any stored error codes related to the AC system.
4
Check the refrigerant level using a manifold gauge set to determine if it is low.
5
Inspect for visible leaks in the AC hoses and components.
6
Test the AC blend door actuator for proper operation.

Solution

1. Preparation

Gather necessary tools and parts.
Ensure the vehicle is parked on a level surface.
Disconnect the negative battery terminal for safety.

2. Recharge Refrigerant

Tools Required: Manifold gauge set, refrigerant canister
Connect the manifold gauge set to the AC service ports (low and high side).
Start the vehicle and turn on the AC to the maximum setting.
Check the low-side pressure; it should be within the manufacturer's specifications (typically 30-40 PSI).
If the pressure is low, add refrigerant according to the manufacturer's specifications, following the instructions on the refrigerant canister.

3. Inspect and Replace AC Compressor (if necessary)

Tools Required: Socket set, torque wrench, AC compressor removal tool
If the compressor is not engaging:
- Disconnect the electrical connector from the compressor.
- Use a multimeter to check for voltage at the connector while the AC is on. If no voltage, the issue may be electrical.
- If voltage is present and the compressor does not engage, proceed to replace the compressor.
Remove the drive belt from the AC compressor.
Unbolt the compressor from its mounting bracket and remove it from the vehicle.
Install the new compressor and tighten the bolts to the manufacturer's torque specifications.
Reconnect the electrical connector and the drive belt.

4. Check AC Condenser and Components

Tools Required: Visual inspection tools
Inspect the AC condenser for debris, damage, or blockages.
Clean any debris from the condenser using compressed air or a soft brush.
Ensure that the condenser fan is operational.