How to Replace an Air Conditioning Compressor Relay

Relays are used in many circuits throughout your vehicle. One such circuit is that of the A/C compressor. The compressor has a belt driven clutch which is cycled on and off to keep your A/C blowing cool. Power is supplied to this clutch through a relay.

A relay is a simple device composed of a coil and set of contacts. When current passes through the coil, a magnetic field is formed. This field draws the contacts together and completes the circuit.

The electronic control module monitors the status of sensors in your vehicle to determine if the conditions are correct for A/C operation. If these conditions are met, the module will energize the A/C relay coil when the A/C button is pushed. This allows power to flow through the relay to the compressor clutch, turning your A/C on.

Part 1 of 2: Locate your A/C relay

Material Needed

  • Owner’s manual

layout of the AC system

Step 1: Locate the A/C relay. The A/C relay is typically found in the underhood fuse box.

Consult your owner’s manual for the exact location.

Part 2 of 2: Replace your A/C relay

Materials Needed

  • Pliers
  • Protective gloves
  • Safety glasses

hand removing the relay

Step 1: Remove the relay. Remove the A/C relay by pulling it straight up and out.

If it is difficult to grasp, you can gently use pliers to remove it.

  • Warning: Be sure to wear safety goggles and gloves at all times.

Step 2: Purchase the new relay. Note the year, make, model and engine size of your vehicle and take the relay with you to your local parts store.

Having the old relay and the vehicle information will enable the parts store to supply you with the correct, new relay.

installing the new relay

Step 3: Install the new relay. Install the new relay by aligning its terminals with the slots in the fuse box and carefully push it in.

turning on the AC

Step 4: Test the A/C. Test the A/C to see if it’s working. If it is, then you have successfully replaced the compressor relay.

Th A/C compressor relay is a small part that plays a big role, as with many parts in your car. Luckily, it is an easy fix if one goes bad, and hopefully replacing it will get your car’s system back to working condition. If your A/C is still not working, you should have your A/C system inspected by a trained professional.


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Greg

22 years of experience
333 reviews
Greg
22 years of experience
Toyota Corolla L4-1.8L - AC is not working - San Tan Valley, Arizona
Greg was very knowledgeable and shared all of the information and recommendations for my vehicle. He is personable and does a great job. Thank you Greg!
Nissan Rogue - AC is not working - Surprise, Arizona
Very happy Greg was able to come back, since he originally installed my compressor. He's honest, forthcoming, and explains exactly what he checks.and exactly what he does! I'm pleased yet again with my appointment! AND I have a/c again! Thanks so much!

John

27 years of experience
1019 reviews
John
27 years of experience
Kia Forte L4-2.0L - AC is not working - Houston, Texas
I really like this guy. He was direct, straight to the point & fairly honest about other things I already knew what was wrong with my car. I honestly felt like I could actually trust and believe In the guys integrity.
Nissan Rogue Sport - AC is not working - League City, Texas
Quick, efficient, detailed, professional. Everything you’re looking for in a mechanic! HIGHLY recommend him. Thank you so much!!

Benji

22 years of experience
277 reviews
Benji
22 years of experience
Honda Accord L4-2.4L - AC is not working - Phoenix, Arizona
Benji was running behind on his appointments. He called to give me very early notice to plan accordingly since he was 20 minutes behind. He's super friendly, knowledgeable, and a pleasure to work it. I would work with Benji again for my auto needs and recommend him to people I know.
GMC Yukon - AC is not working - Chandler, Arizona
On time, friendly, and professional. Gave thorough explanation of findings and answered all my questions - I would not hesitate in recommending Benji to anyone.

Peter

25 years of experience
514 reviews
Peter
25 years of experience
Toyota Matrix L4-1.8L - AC is not working - Los Angeles, California
Peter was incredibly detailed and was able to diagnose and fix my AC issue. As a new car owner, 10/10 I would hire Peter again to help diagnose and fix the issues on my Toyota. Thank you!!!
Ford Taurus - AC is not working - Granada Hills, California
Great experience! Peter lives close by and contact me to see if he could come by a day early at the end of his day. He made the repair, gave me instructions on what to look for in the future and all took 30 minutes.

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