my Toyota Highlander Third Generation (2014-2019) air conditioning is not blowing cold air

Toyota Highlander Third Generation (2014-2019)

Error Codes

2-4 hours

Time

medium

Difficulty

medium

Severity

3 min read

592 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.
•Handle refrigerants with care and follow local regulations for disposal.

Symptoms

•No cold air coming from the vents
•AC compressor not engaging
•Unusual noises when the AC is turned on
•AC system blowing warm air intermittently
•Increased humidity inside the vehicle
•"AC" light blinking on the control panel

Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to identify potential issues related to the AC system.
2
Check the refrigerant level using a manifold gauge set to determine if it is low or overcharged.
3
Inspect the AC compressor visually for signs of damage or leaks.
4
Test the AC control module and switches for proper operation.
5
Verify the condition of the AC condenser and evaporator for blockages or debris.
6
Inspect electrical connections to the compressor for continuity and proper voltage.

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 can with R-134a
•Socket set
•Wrench set
•Torque wrench
•Multimeter

Parts Required

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

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Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to identify potential issues related to the AC system.
2
Check the refrigerant level using a manifold gauge set to determine if it is low or overcharged.
3
Inspect the AC compressor visually for signs of damage or leaks.
4
Test the AC control module and switches for proper operation.
5
Verify the condition of the AC condenser and evaporator for blockages or debris.
6
Inspect electrical connections to the compressor for continuity and proper voltage.

Solution

1. Preparation

Ensure the vehicle is parked on a flat surface and the engine is off.
Disconnect the battery's negative terminal to prevent electrical shocks.
Gather necessary tools and parts.

2. Recharge Refrigerant

Tools Required: Manifold gauge set, refrigerant can with R-134a.
Sub-steps:
1. Connect the low-pressure side of the manifold gauge to the AC service port.
2. Start the engine and turn on the AC to the maximum setting.
3. Check the gauge reading; if low, add refrigerant according to specifications (typically R-134a).
4. Monitor the high and low-pressure gauges to ensure they reach appropriate levels (typically 30-40 psi on low side and 200-250 psi on high side).
5. Disconnect the manifold gauge set and replace the service port cap.

3. Replace AC Compressor

Tools Required: Socket set, wrench set, torque wrench, AC compressor oil.
Sub-steps:
1. Remove the serpentine belt from the AC compressor.
2. Disconnect electrical connectors and refrigerant lines from the compressor.
3. Unbolt and remove the old compressor from its mounting bracket.
4. Install the new compressor, ensuring to add the specified amount of AC compressor oil.
5. Torque the mounting bolts to the manufacturer’s specifications.
6. Reconnect the refrigerant lines and electrical connectors.

4. Test and Inspect

Tools Required: Multimeter.
Sub-steps:
1. Reconnect the battery's negative terminal.
2. Start the vehicle and run the AC system.
3. Use a multimeter to check that the compressor is receiving voltage.
4. Verify that the AC is blowing cold air and monitor for any unusual noises.