why does my Volkswagen Golf MK7 (2015-2019) AC blow warm air

Volkswagen Golf MK8.5 (2024-Present)

Error Codes

2-4 hours

Time

medium

Difficulty

medium

Severity

3 min read

528 words

Problem Statement

Complete guide to fixing AC that blows warm air in Volkswagen Golf MK7. Includes symptoms, diagnostic steps, tools required, and repair procedures.

Affected Component

HVAC

Estimated Time

2-4 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect the battery before working on electrical components.
•Wear safety glasses and gloves when handling refrigerants to prevent injury.

Symptoms

•AC system is not cooling the air
•AC compressor does not engage
•Unusual noises coming from the AC system
•Moisture or water pooling under the vehicle
•AC control panel lights are functioning but not cooling

Diagnostic Steps

1
Check the AC control settings to ensure the system is set to 'cool' and the temperature is adjusted correctly.
2
Inspect the AC compressor visually for any signs of damage or leaks.
3
Use an OBD-II scanner to check for any fault codes related to the AC system.
4
Check the refrigerant level with a gauge to determine if the system is low on refrigerant.
5
Inspect the AC condenser for blockages, dirt, or physical damage.
6
Test the AC relay and fuse to ensure they are functioning correctly.

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
•Refrigerant gauge set
•Socket set
•Wrenches

Parts Required

•R-134a refrigerant
•AC compressor (if replacement is necessary)
•AC compressor oil (if replacing the compressor)

Related Faults

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Diagnostic Steps

1
Check the AC control settings to ensure the system is set to 'cool' and the temperature is adjusted correctly.
2
Inspect the AC compressor visually for any signs of damage or leaks.
3
Use an OBD-II scanner to check for any fault codes related to the AC system.
4
Check the refrigerant level with a gauge to determine if the system is low on refrigerant.
5
Inspect the AC condenser for blockages, dirt, or physical damage.
6
Test the AC relay and fuse to ensure they are functioning correctly.

Solution

1. Preparation

Gather all necessary tools and parts.
Ensure the vehicle is parked on a level surface and the engine is turned off.
Disconnect the negative battery terminal to avoid electrical issues.

2. Recharge Refrigerant

Tools Required: Refrigerant gauge set, R-134a refrigerant.
Locate the low-pressure service port on the AC system.
Connect the refrigerant gauge set to the low-pressure port.
Start the engine and set the AC to maximum cooling.
Slowly add R-134a refrigerant until the recommended pressure is reached (usually between 30-40 psi).
Disconnect the gauge set and replace the service port cap.

3. Replace AC Compressor (if necessary)

Tools Required: Socket set, wrenches, AC compressor replacement kit.
Remove any engine covers or components obstructing access to the AC compressor.
Disconnect the electrical connector from the AC compressor.
Remove the refrigerant lines (be prepared for some refrigerant to escape).
Unbolt the AC compressor from its mounting bracket.
Install the new compressor by reversing the removal steps.
Reconnect the refrigerant lines and electrical connector.

4. Test the System

Reconnect the negative battery terminal.
Start the engine and turn on the AC to check for proper operation.
Monitor the system for any unusual noises or leaks.