How to Fix Car AC Not Working

Car air conditioning that blows warm air is almost always caused by low refrigerant, a compressor issue, or a blocked condenser.

Likely causes

• Low refrigerant (most common cause)
• Faulty AC compressor
• Blocked or dirty condenser
• Electrical fault in the AC system
• Cabin air filter blocked

Step-by-step fix

1. 1
   Turn the AC on correctly

   Press the AC button (snowflake symbol) and set the fan to maximum. Make sure it is not set to recirculation only.

2. 2
   Check the cabin air filter

   A clogged cabin filter reduces airflow. It is usually located behind the glove box. Replacing it takes 5 minutes and costs under £15.

3. 3
   Regas the AC

   Low refrigerant is the most common cause of warm AC. Many garages offer an AC regas service for £40-80. This should be done every 2-3 years.

4. 4
   Listen for the compressor

   With AC on, listen for a clicking sound when you increase revs — this is the compressor clutch engaging. No click may indicate a compressor or electrical fault.

5. 5
   Check for visible damage to the condenser

   The condenser sits in front of the radiator. Check for bent fins or debris blocking it.

6. 6
   Take it to an AC specialist

   If regassing does not fix it, a specialist can pressure test the system and identify leaks or component failures.

Frequently asked questions

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