Honda Civic AC Problems (Not Cold/Not Turning On/Intermittent)

A car’s air conditioning (AC) problems can be very challenging to diagnose. Sometimes, it can be a simple matter of replacing a circuit breaker if it doesn’t turn on. But in some cases, like with an intermittent fluctuation in temperatures on your Honda Civic, a lot more detailed investigation needs to take place.

Honda Civic AC problems often stem from a lack of refrigerant, usually due to leaks in the system. Identifying and repairing the leak points, followed by recharging the refrigerant, typically resolves the issue.

Another cause could be a malfunctioning AC compressor. If the compressor isn’t engaging, it could be due to an electrical issue, a seized compressor, or a broken serpentine belt. Diagnosing the exact cause and repairing or replacing the faulty components will typically restore AC function.

Honda Civic AC Problems (Not Cold/Not Turning On/Intermittent)

In this article, I’ll go over the different Honda Civic AC system components and show you how to diagnose each one. Then, I’ll give you some ideas on how to fix each problem. The types of tools and materials you’ll need will also be covered in detail.

Honda Civic AC Is Not Working/Not Turning On

Check To See if There Is Electricity Going to the Compressor

The AC clutch is part of the compressor assembly and is located just in front of the belt pulley. It engages when the sensor gives a signal to the system to activate the compressor for more cooling. For that reason, it should eventually start to spin when the system is on. If it doesn’t, it could mean there is no electrical current to the system.

Before replacing the compressor assembly, or the clutch, check the relay first. It is under the hood on the driver’s side and is located inside the circuit breaker panel. Pull the relay out and shake it. If there is a rattling noise present, that means the internal switch is broken, and the relay needs to be replaced.

The circuit to the compressor has been broken, and the AC will not turn on. Replacing the relay from the start is much more economical than replacing the compressor.

Honda Civic AC Not Blowing Cold Air

Check the Coolant Pressure

Here are the steps for making sure there is enough coolant in the system:

Ensure that the valves on the manifold gauge are in the closed position.
Connect the low-pressure side of the gauge (usually marked in blue) to the low-pressure port.
Connect the high-pressure side of the gauge (usually marked in red) to the high-pressure port.
Place an air conditioning diagnostic thermometer into the center vent, which is used to monitor temperature variations during the pressure check (40°F or 4.44°C is optimal for normal operation at sea level).
Start the engine.
Set the air conditioner to manual with the fan speed on the third setting, but not on high. Set the recycling button to the “max air” position.
With the help of another person, maintain engine RPM at 2000.

How To Interpret Pressure Gauge Readings

Both gauges read low: If both the low and high sides of the gauge indicate low pressure, that usually means a low charge, and the system needs to be refilled with refrigerant.
Low side is low, high side is high: If the low side pressure is low, and the high side pressure is high, it usually indicates a system blockage.
Low side high, high side low: If the low side pressure is high, and the high side pressure is low, that will usually indicate a faulty compressor.
Low side high, high side high: If both the low and high sides indicate high readings, that usually means the system is overcharged.

Honda Civic AC Not Getting Cold

The AC system may need refrigerant. The most common type is R134A. Fill the system according to the manufacturer’s specifications.

A good choice for refrigerant is ZeroR. It comes in a 3-pack and can fit on most portable gauges you can purchase separately.

Honda Civic Air Conditioner Works Intermittently

Inspect the clutch for obvious corrosion and damage. Rust, corrosion, and metal flaking are all signs the clutch is on its way to failing soon. Before replacing the clutch or compressor, make sure there are no underlying electrical problems.

Honda Civic AC Clutch Not Engaging

Check to make sure the AC clutch is engaging the compressor. Do this by attaching a voltmeter to the bare portion of the power wire going to the compressor and applying 12 volts to the circuit. You should hear a clicking sound. That is the clutch engaging the compressor. Also, with the power applied, the compressor belt pulley will be hard to turn, signifying that the AC clutch is engaging properly.

It is difficult and expensive to replace the AC clutch on the Honda Civic. For that reason, it is more practical and economical to spend a little more money and replace the entire compressor assembly. The nice thing is that most of the time, it comes with the clutch already installed.

Honda Civic AC Cooling Fan/Condenser Fan Not Working

If the fan doesn’t turn on while the AC system is on, follow these steps to troubleshoot it:

Check the fuse.
Check the AC relay.

If both the fuse and relay are okay, check the fan directly at the plug using a voltage tester. If the fan doesn’t run with the voltage applied, replace it.

Honda Civic AC Not Cold at Idle

Usually, when the car is cooling while driving, but not when it is idle, that indicates that the cooling fan may be faulty. It is best to check it using the above troubleshooting steps and replace it if necessary. Also, it may be a good idea to check the refrigerant levels.

Honda Civic Driver Side AC Not Working

The most common cause for the left side being warmer than the right side is not enough refrigerant in the system. The evaporator core is not getting enough refrigerant to carry over to the driver’s side, and it is warming before it can get all the way through the system.

Another reason you might see temperatures cooler on the right and warmer on the left is a restriction in the AC system. There may be a blockage in either an AC line or one of the components. When this happens, it will mimic not having enough refrigerant.

Honda Civic AC Compressor Does Not Turn On

Here are five of the most common causes for the AC compressor to not turn on:

AC system circuit breaker: These are located in the circuit breaker panel on the driver’s side dashboard.
Compressor control relay: It is located in the relay box under the hood.
Not enough refrigerant in the system: The AC compressor will not turn on unless the pressure sensor detects enough refrigerant in the system.
Faulty AC compressor: The most common sign of a faulty AC compressor is a growling noise, which may be from a failure of the bearings.
Faulty control switches: Climate control switches on the dashboard can wear out and may need to be replaced.

Honda Civic AC Not Working When Hot

If you’ve gone through the troubleshooting steps above and the ac compressor is working, it may be the car’s computer. Scan it to see if you get an AC code. If you get multiple codes throughout several systems, the ECU may need to be reprogrammed.

Honda Civic AC Light Not Working

The most obvious thing to do is to replace the bulb. But that is no easy task since you will have to remove the entire dashboard to gain access.

The easiest place to start before doing all that is the circuit breaker. If it has failed, it will extinguish the AC light. Replacing the AC circuit breaker first can save a lot of time and aggravation.

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