how to fix the air conditioning in my Toyota Highlander Third Generation (2014-2019) that stopped bl...

Toyota Highlander Third Generation (2014-2019)

Error Codes

2-4 hours

Time

medium

Difficulty

medium

Severity

3 min read

551 words

Problem Statement

Learn how to diagnose and fix the AC not blowing cold air in a 2014-2019 Toyota Highlander. Step-by-step guide with tools and parts required.

Affected Component

HVAC

Estimated Time

2-4 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect the battery before working on electrical systems
•Ensure the engine is off and cool to prevent burns

Symptoms

•AC system running but no cold air is emitted
•Increased cabin humidity or musty smell
•AC compressor not engaging
•Unusual noises from the AC system (e.g., clicking or hissing)
•Refrigerant leak visible around connections or components

Diagnostic Steps

1
Check the AC system controls to ensure proper settings (temperature and fan speed)
2
Use an OBD-II scanner to check for any related trouble codes
3
Inspect the AC compressor for engagement by observing the clutch operation
4
Measure the refrigerant pressure using a manifold gauge set
5
Inspect for any visible refrigerant leaks around hoses and the compressor
6
Check the 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
•Basic hand tools (sockets, wrenches)
•Safety goggles
•Gloves

Parts Required

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

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Diagnostic Steps

1
Check the AC system controls to ensure proper settings (temperature and fan speed)
2
Use an OBD-II scanner to check for any related trouble codes
3
Inspect the AC compressor for engagement by observing the clutch operation
4
Measure the refrigerant pressure using a manifold gauge set
5
Inspect for any visible refrigerant leaks around hoses and the compressor
6
Check the cabin air filter for clogs or blockages

Solution

1. Preparation

Gather tools and parts needed before starting.
Tools Required:
- OBD-II scanner
- Manifold gauge set
- Basic hand tools (sockets, wrenches)
- Safety goggles and gloves
Safety Warnings:
- Disconnect the battery before working on electrical systems.
- Ensure the engine is off and cool to prevent burns.

2. Recharge Refrigerant

Connect Manifold Gauges:
- Attach the low-pressure side hose (blue) to the low-side service port and the high-pressure side hose (red) to the high-side service port.
Check Refrigerant Levels:
- Read the pressures displayed on the gauges. If low, proceed to recharge.
Recharge System:
- Attach the refrigerant can to the low-pressure hose.
- Open the valve on the refrigerant can and start the vehicle.
- Monitor pressures and add refrigerant until the appropriate levels are reached (typically 30-45 psi on low side when running).

3. Inspect and Replace Components

Inspect AC Compressor:
- Check the compressor for any signs of damage or leaks.
- If the clutch does not engage, consider replacing the compressor.
Replace Cabin Air Filter:
- Open the glove compartment and remove the filter cover.
- Replace the old cabin air filter with a new one.

4. Check Electrical Connections

Inspect Wiring and Fuses:
- Check the AC relay and fuse in the fuse box. Replace if blown.
- Examine the wiring for any signs of wear or damage.

5. System Leak Test

Perform Dye Test:
- Inject UV dye into the AC system to identify leaks.
- Use a UV light to inspect for leaks after running the AC for a short period.