Q: ac compressor clutch not engaging

asked by on January 11, 2017

Compressor quit suddenly while driving , cooled great prior to that.( I did here a noise a few minutes prior to noticing it wasn't cooling but thought it was ridges in the road) A shop told me the compressor was bad but due to the high price I got a second opinion. The second mechanic told me that the clutch was not engaging and that it could be just a bad coil and that he couldn't verify a bad compressor without the clutch engaging. He said the system has pressure and that the coil is getting power. What are the odds that the coil is the only problem and I could expect to get a few more years out of the compressor?

My car has 111000 miles.
My car has an automatic transmission.

AC is not working Inspection $96.46 - $106.46 Get a Quote

Let’s assume the clutch is not engaging. The clutch coil should simply be tested to determine if coil failure is the cause and it’s easy to do. The integrity of the clutch coil can be tested on the car using an ohmmeter. Of course, the Factory Service Manual (FSM) specification for your clutch coil is the one to compare against, but typically an A/C compressor clutch coil will have a measured resistance (cold) in the range of 2 to 5 ohms. If the resistance of the coil reads outside that range (or, more accurately is not within the FSM specification) then there’s something wrong with the coil. The diode in the circuit (if equipped) should be tested as well. If the coil is bad, it can be replaced and during replacement the compressor is evaluated for freewheeling (i.e., normal) operation. If it is not seized, you can likely re-use it. While any compressor is out of a vehicle, it’s always a good idea to re-seal it. The parts are very cheap but there is labor involved. Mobile replacement of the clutch assembly (including the coil) will save you money on the repair. If you desire that a certified professional from YourMechanic test the coil and evaluate the compressor’s suitability for repair (i.e., refurbishment with a new clutch/coil assembly) please simply request an A/C system diagnostic. Please let us know if you have follow up questions or additional concerns.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

What others are asking

Bleeding Hydraulic Clutch Line w/ Broken Bleeder Valve

You most likely have a leaking slave cylinder inside the transmission clutch housing. This is why you are loosing fluid. This will cause air to get into the hydraulic system and cause the spongy pedal. Have the transmission removed and...

Rattling coming from the bottom of the car during idling

The rattle at idle could be caused by a variety of issues, such as any loose parts or panels, fuel injector noise, or the engine top end. The deeper rattle could also be caused by a few items such as...

My Mercedes Benz Gl450 will tilt to the right quite a lot and the air matic won't work and the front right wheel almost touches the fe

This is likely a compressor issue. The compressor may be faulty or may have a bad connection. This can be tested several ways. You may have a code available from the computer which explains more about the compressor issue. You...

Ac clutch blowing fuse

The AC would have to be diagnosed to see if the clutch or compressor is blowing the fuses. You could try disconnecting the compressor to see if the AC is still blowing fuses. If it does, then further diagnostics would...

We have replaced the compressor in my husband's Toyota Tacoma 3 times in as many years. What could cause them to keep failing? 2001 Toyota Tacoma

Hello - when the AC compressor fails, it can deposit a fairly large amount of metallic debris throughout the AC piping and components. It is VERY difficult, even with chemical flushes, and added filters, to get all the grit out...

Gas pedal not going down when pressed.

The throttle pedal may be blocked by your carpet. Check the pedal to make sure it is not being blocked. The pedal operates a cable and then to the throttle body assembly. Each of these would need to be checked...

Do I need to keep refrigerant in my A/C compressor during winter months

The refrigerant inside the compressor has nothing to do with the compressor pulley turning freely when the compressor is not engaged. If the pulley is not turning free then the bearing inside the pulley will need to be replaced. If...

Why Is My AC Blowing Warm Air?

There are quite a few reasons an A/C system will cease to provide you with cold air. Air conditioning systems are one of the more complex systems on a passenger vehicle. Without getting into to all the complexities and science...

Replace crank seal and harmonic balancer

What you must of seen is a mechanic using sealer on the outside of the seal so it will seal any leaks between the seal and the front cover. This is okay to do. Before the balancer is installed you...

Related articles

How Long Does a Fan Clutch Last?
One One of the most important parts within the cooling system of your vehicle is the fan clutch. It’s not a part that comes up often, as it’s usually pretty consistent. However, if this part should stop working the entire...
Symptoms of a Bad or Failing AC Accumulator
Common signs you need to repair your AC accumulator include rattling noises during operation, noticeable refrigerant leaks, and a moldy smell.
Why Does My AC Rattle When I Turn It On?
Common reasons why a car AC system makes a rattling noise is due to a failing AC compressor, worn serpentine belt, or worn out AC compressor clutch.