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3 Technical Tips to Find Out What’s Wrong with Your Car’s A/C System

It’s summer, and it can be really annoying when you find out that your car’s A/C system has given up. 

Many reasons could cause your A/C unit to stop working as it should. It might be low on refrigerant, an electrical or mechanical compressor clutch failure, or it could be a faulty HVAC module. If these terms already sound like rocket science to you, you might as well get your vehicle checked out at a nearby car ac repair shop. 

This post will go over some quick A/C system tips that could help you figure out whether you need to pay a visit and spend money at a workshop. 

Checking The A/C Control System

Generally, a compressor stops compressing when there’s a power issue with the clutch, or it is locked up and damaged. We will begin by testing the electrical portion of it. To do this, you must first know where to find the relay switch box. You can refer to your owner’s manual or search online to find out where the ac compressor relay slot is. Most of the time, you will be able to find it below the number marked under the box’s lid with a snowflake sign.

Once you find it, you must remove that and check if there’s power coming from the fuse using a test light setup. You need to hook the alligator clip into the ground and make contact between the test light and the relay socket pin. If the test light works, your compressor controls are working fine. 

Once ready, you must start the engine and turn on the A/C button. If the test light lights up, you have no trouble with the buttons of the interior controls or the climate control system. 

Problems That Could Occur In The Engine Bay

Here, you must check whether the compressor receives power. To do this, you require manually operated relay switches, which have the on/off controls on the relay. Plug this into the compressor and check for the clicking sound of the clutch. 

If it clicks, you know that the clutch is fine and is free from problems such as damaged wires, grounding issues, or burnt coils. These issues would’ve prevented it from engaging and making the sound. 

Refrigerant Check

The next thing you have to do is take the caps off of your refrigerant service ports. You will need a small screwdriver to push the Schrader valve inside the service port. If it momentarily gushes the gas out, making a ‘whoosh’ sound, it means that there’s enough freon in your A/C system. It’s really simple. On the other hand, if nothing happens when you push it, you know you’re out of refrigerant. This could probably indicate a leak in the system. It can be just low enough that it’s not enough to turn on the pressure switch. 


So we have power coming from the dash to turn on the relay which means we’re good inside the dash. And we can get power to the compressor, and the clutch works. So it’d be very likely that this system might be low on freon. 

If it’s just a little bit low on refrigerant, there’s no way for you at home to know accurately how much is in the system and how much it needs. You require specialized equipment to rectify this issue, costing around $4000-5000, which is not something you’d buy as home garage equipment. It’s a professional buy.  

Certain manufacturers like Honda are extremely picky about how much refrigerant their cars need. If it’s an ounce too much or an ounce too little, it can make it not run at all. So be sure to get your car checked out at a nearby car A/C system repair shop that you trust. 

Featured Image by NoobInNature NIN on Pixabay