How To Check Your A/C Clutch Relay With A Multimeter

How To Check Your AC Clutch Relay With A Multimeter

Your vehicle’s air conditioning system doesn’t seem to be operating. What could be the problem? There is any number of components and parts involved in the air-conditioning system of any vehicle. One problem, however, could be the A/C clutch relay. You may also hear this referred to as an A/C compressor relay or a compressor clutch relay.

To determine whether or not an A/C clutch relay is faulty, there are couple of methods that can be used. One involves a multimeter.

Let’s look at how to use a multimeter to check your vehicle’s A/C clutch relay. After that, a simple relay switch method will be described, in case you don’t have access to a multimeter.

Do You Have a Bad Relay?

Signs and symptoms that you have a bad relay:

  • Your vehicle’s A/C compressor isn’t turning on – It’s normal to notice some type of sound from your compressor clutch when the vehicle’s air conditioning system is turned on. A clicking sound, for example. But the compressor won’t even turn on if there’s a problem with the relay.
  • No cool air flow – Granted, no cool air flow could point a to a vast array of issues with your vehicle’s air conditioning system, but a bad A/C clutch relay is one of them.
  • Cooling is erratic – If the air conditioner in your vehicle is weak or erratic, the compressor may be receiving a depleted load thanks to a faulty relay.

Your vehicle may have a warning light of some sort to let you know if the A/C system of your vehicle is malfunctioning. In some vehicles, the light flashes when there’s a problem. Not all vehicles are equipped with this, however.

A/C Clutch Relay Check with a Multimeter

Obviously, you’ll need a multimeter for this procedure.

  • Remove the relay from the fuse/relay box.
  • The multimeter should be in Ohmmeter or Resistance Measurement mode.
  • Put the range meter in minimum range if you have a manual ranging multimeter (somewhere on the lines of 200 ohms).
  • Connect the multimeter leads across the relay’s coil terminals.
  • You should get a reading on the multimeter of 40 to 120 ohms for a normal coil.
  • A damaged coil will show out of range and the relay will need to be replaced.

A/C Clutch Relay Check Via Relay Swap

You can test your vehicle’s A/C compressor relay without a multimeter, if you feel comfortable. Replace the clutch relay (in the fuse and relay box) with a similar relay that you know is functional (possibly your horn relay). After that, if the A/C works or the flashing warning light stops flashing, the A/C compressor relay should be replaced.

If automotive repair isn’t in your list of talents, an automotive technician can do it for you relatively inexpensively.

We Carry Automotive A/C Compressor Clutches and Assorted Other Parts

R&Y A/C Compressors has all the parts, components, and kits you need for your vehicle’s AC. Some of the products we offer are:

  • Tubes
  • Accumulators
  • Condensers
  • Evaporators
  • … and much more

To reach our customer service department, please call 305-919-8864 between 8:30 AM and 5 PM EST, Monday through Friday. (Saturdays, from 8:30 AM to 2:30 PM.) If you’d rather, you can fill out our convenient online form, send it in, and we’ll respond.

You may also choose to send us an email at [email protected]. We look forward to working with you.