Why is my AC not turning on Subaru?

In most Subarus, the issue boils down to an electrical fault, a faulty compressor clutch, or a low refrigerant charge from a leak. Other common causes include climate-control settings, a blown fuse or relay, or a worn belt that drives the compressor.

This article explains the typical failure modes, how to diagnose them, and when to seek professional help. It covers electrical, refrigerant, mechanical, and control-system factors across popular Subaru models such as the Impreza, Forester, Outback, Crosstrek, and WRX.

Common causes and how they manifest

Below are the typical failure modes you might encounter when the A/C won’t engage, along with what you’ll notice in the cabin and under the hood.

• Blown A/C fuse or a faulty A/C relay, which prevents the compressor from engaging altogether.


• Faulty or seized A/C compressor clutch, so the pulley spins but the clutch doesn’t engage the compressor.


• Low refrigerant charge from leaks, triggering high- or low-pressure switches to block compressor operation.


• Damaged or worn serpentine belt or a failed belt tensioner that stops the compressor pulley from turning.


• Faulty climate-control head or control module that fails to send an A/C request to the compressor.



• Overheating condenser or a non-working condenser fan, which reduces cooling efficiency and can trigger protective shutoffs.

In practice, the problem may show up as no cold air, the blower running without cooling, or intermittent cooling behavior depending on the fault.

How to diagnose at home

These steps help you narrow down the cause before visiting a shop. The list starts with quick checks you can perform at the dash and ends with more involved checks that may require tools.

1. Ensure the A/C is turned on, the mode isn’t set to hot-defrost-only, and the cabin temperature is set to a cold setting. Some Subaru systems delay engagement in certain modes.


2. Inspect fuses and relays for the A/C circuit in the main fuse box and, if accessible, the engine bay fuse box. Replace any blown fuse with the correct rating and re-test.


3. Check the serpentine belt for cracks, glazing, or looseness. A worn belt can prevent the compressor from turning.


4. Listen for the compressor clutch engagement when you switch A/C on. A brief clicking sound and visible pulley movement indicate engagement; no sound may point to a clutch or control signal issue.


5. If you have access to a refrigerant pressure gauge set, measure the system pressures. Very low readings often indicate a leak; avoid adding refrigerant unless you know the system type and have proper training.


6. Look for signs of leaks around hoses, fittings, and the compressor (oil residue or UV dye traces). Leaks usually require repair rather than “topping up.”


7. Run a basic scan with an OBD-II adapter to check for HVAC-related fault codes that can point to sensors or control-module problems.

These checks help determine whether the issue is electrical, refrigerant-related, or mechanical. Some steps require tools or professional care; if in doubt, consult a trained technician.

Subaru-specific system notes

Subaru climate systems can vary by model year and trim. Some models use automatic climate control that can override user settings or delay A/C engagement in certain modes (defrost, economy mode, or auto settings). The A/C pressure switch and the condenser fan behavior are also common failure points across many generations. If you’re working on a Subie with a cabin air filter and a dedicated A/C relay, refer to your owner’s manual for fuse locations and relay designations, as these can differ between Impreza, Forester, Crosstrek, and Outback configurations.

When to seek professional help

If basic checks don’t restore cooling, or you notice refrigerant odor, oily residue at connections, grinding/clunking noises from the compressor, or persistent non-engagement of the clutch, arrange a diagnostic with a Subaru-certified technician or a reputable A/C shop. Handling refrigerants requires proper equipment and training, and improper recharging can damage the system or violate local regulations.

Summary

The most common reasons a Subaru A/C won’t turn on are electrical faults (fuses/relays or control modules), a failing or seized compressor clutch, low refrigerant from leaks, and belt or condenser issues. Start with simple checks: confirm settings, inspect fuses/relays, inspect the drive belt, and listen for clutch engagement. If these steps don’t resolve the problem, or if you detect leaks or unusual noises, seek professional diagnostics and service. Regular maintenance and leak repair help prevent future A/C failures across Subaru models.

Why is my AC not kicking on in my car?

Your car's AC may not be turning on due to a simple issue like a blown fuse or a clogged cabin air filter, or it could be a more significant problem like low refrigerant, a faulty compressor, or electrical issues with sensors and wiring. To diagnose the problem, check the fuse, air filter, and look for obvious blockages on the front condenser, but be prepared to consult a professional for more complex issues. 
Simple checks

• Blown fuse: A blown AC or blower motor fuse is a common and easy fix, according to Reddit users. 
• Clogged cabin air filter: A dirty filter can restrict airflow and prevent the AC from working properly, as Meineke and Gene Messer Hyundai explain. 
• Debris on condenser: Check the condenser at the front of the car for blockages like leaves, dirt, or bugs that might be restricting airflow, notes Carsales. 

This video shows how to check the AC relay and diagnose a common problem with car air conditioning systems: 54sAutoFunYouTube · Aug 16, 2021
More complex issues

• Low refrigerant: A lack of refrigerant is a very common cause. This could be due to a leak in the system, such as a failing seal or a hole in a hose, explains AutoZone.com and Gene Messer Hyundai. 
• Faulty compressor: The compressor is a critical component that circulates the refrigerant. It can fail from lack of use, wear and tear, or a seized clutch, says Auto Works Automotive Service Center. 
• Electrical problems: Beyond the fuse, electrical issues can include a bad pressure switch, faulty wiring, a broken relay, or a problem with the AC control module itself, as detailed by AutoZone.com and Reddit. 
• Broken belt: The AC compressor is driven by a belt. If this belt is broken or slipping, the compressor won't operate, notes Gene Messer Hyundai. 
• Faulty condenser fan: The condenser, which is in front of the radiator, needs a cooling fan to operate. If the fan isn't working, the AC won't cool properly. 

What to do next
If a quick check of the fuse and cabin air filter doesn't solve the problem, it's best to have a qualified technician inspect the system, especially if you suspect low refrigerant or an electrical issue. A professional can use specialized tools to accurately diagnose and repair the problem, says Auto Air Con Parts.

How to tell if a Subaru AC compressor is bad?

Common Signs of a Failing Subaru AC Air Compressor

1. High Cabin Temperatures. One of the very first signs of a failing compressor is the failure of the air conditioner to blow cold air as it used to do.
2. Loud Noise.
3. Compressor Clutch Not Moving.

How much to fix AC in Subaru?

On average, the cost for a Subaru Forester Car AC Repair is $372 with $176 for parts and $196 for labor. Prices may vary depending on your location.

Why is my AC not working in my Subaru?

If your Subaru's AC isn't working, the most common reasons include low refrigerant from a leak, an electrical issue like a blown fuse or bad relay, or a problem with the compressor or condenser. First, check for a clogged cabin air filter, then a blown fuse or faulty AC relay. If those don't solve it, it's likely a refrigerant leak, a faulty compressor clutch, or a problem with the condenser. A professional is best equipped to diagnose and fix these issues, especially those involving refrigerant. 
This video explains the common issues with Subaru AC and how to troubleshoot them: 59sMrSubaru1387YouTube · Apr 28, 2024
Simple checks

• Cabin air filter: A clogged filter can restrict airflow, even if the AC system is working. 
• Fuses and relays: Check the fuse box for a blown AC fuse and test the AC relay by swapping it with a known working one (like the horn relay). 

Potential causes requiring professional help

• Low refrigerant: A common cause is a leak in the system's seals or hoses, which can lead to low refrigerant levels. 
• Faulty compressor: The compressor can fail due to a bad clutch or internal damage. A loud noise or a compressor clutch that doesn't spin are signs of a failing compressor. 
• Faulty condenser: The condenser can become clogged or damaged by contaminants. 
• Electrical issues: More complex electrical problems, such as a faulty AC/heater control module, can prevent the system from working. 

You can watch this video to learn about AC compressor failure: 58sMrSubaru1387YouTube · Aug 4, 2024
When to see a mechanic

• If a refrigerant leak is suspected.
• If you hear loud noises coming from the AC compressor.
• If the compressor clutch is not engaging.
• If you are uncomfortable working with electrical components or car systems. 

This video shows how to replace a faulty AC compressor: 53sMrSubaru1387YouTube · Jul 2, 2025