how to fix the AC not blowing cold air on my Toyota Highlander Fourth Generation (2020-present)

Toyota Highlander Fourth Generation (2020-present)

Error Codes

2-4 hours

Time

medium

Difficulty

medium

Severity

4 min read

640 words

Problem Statement

Learn how to diagnose and fix AC not blowing cold air in Toyota Highlander (2020-present). Step-by-step guide with symptoms, tools, and solutions.

Affected Component

HVAC

Estimated Time

2-4 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect the battery before working on electrical components
•Allow the vehicle to cool before working on the AC system

Symptoms

•AC system not cooling air
•AC compressor not engaging
•Unusual noises from the AC unit
•Warm air blowing from vents
•Decreased airflow from vents
•AC warning light illuminated on the dashboard

Diagnostic Steps

1
Check AC settings to ensure it's set to the correct mode and temperature
2
Inspect AC refrigerant level using a manifold gauge
3
Scan for error codes using an OBD-II scanner
4
Examine AC compressor for signs of damage or leaks
5
Test AC relay and fuses for continuity and functionality
6
Inspect cabin air filter for clogs or blockages

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
•Multimeter
•Socket set
•Screwdrivers
•Safety goggles

Parts Required

•Refrigerant (R-134a or R-1234yf, depending on the system)
•AC compressor (if replacement is necessary)
•AC drive belt (if worn)

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Diagnostic Steps

1
Check AC settings to ensure it's set to the correct mode and temperature
2
Inspect AC refrigerant level using a manifold gauge
3
Scan for error codes using an OBD-II scanner
4
Examine AC compressor for signs of damage or leaks
5
Test AC relay and fuses for continuity and functionality
6
Inspect cabin air filter for clogs or blockages

Solution

1. Preparation

Tools Required: OBD-II scanner, manifold gauge set, multimeter, socket set, screwdrivers, and safety goggles.
Safety Warning: Disconnect the battery before working on electrical components.

2. Recharge AC System

Locate the Low-Pressure Service Port: Find the low-pressure service port of the AC system (usually located on the larger diameter AC line).
Connect Manifold Gauges: Attach the manifold gauge set to the low-pressure service port.
Check Refrigerant Level: Read the gauge to determine if the refrigerant level is low.
Add Refrigerant: If low, connect the refrigerant can to the manifold gauge and follow the instructions to add refrigerant until the pressure is within the manufacturer's specifications.
Monitor While Running: Start the engine and turn on the AC to monitor the pressures to ensure the system operates correctly.

3. Replace AC Compressor (if faulty)

Remove the Drive Belt: Use a socket set to relieve tension and remove the serpentine belt from the AC compressor.
Disconnect Electrical Connectors: Carefully unplug electrical connectors from the AC compressor.
Remove AC Lines: Use the appropriate tools to detach the AC lines from the compressor, ensuring to recover any remaining refrigerant if necessary.
Unbolt the Compressor: Remove the bolts securing the compressor to the engine block and take out the compressor.
Install New Compressor: Place the new compressor in position, securing it with bolts to the engine block.
Reconnect AC Lines and Electrical Connectors: Reattach the AC lines and electrical connectors to the new compressor.
Reinstall the Drive Belt: Place the serpentine belt back onto the compressor.