A/C Compressor clutch not engaging

Hey guys so as the title states my A/C clutch is not spinning with the pulley. First off let me state the number of things I have already done to diagnose the problem. Of course worst case scenario would be to replace the compressor but I haven't gone that far. So far I have:
1. Replaced A/C line that had a crack and vacuumed system and refilled with refrigerant.
2. Checked all A/C related fuses
3. Replaced the A/C compressor relay
Now after doing all of that I figured I should make sure there is power going to the compressor in the first place. So I hooked up a test light to my battery and verified the ground was good. However it appears there was no power going to the plug attached to the compressor. I also noticed no "clicking" of the relay when I had someone turn the A/C on and off.
Basically I'm thinking this is an electrical issue but I'm stuck as to what to do next as the problem now seems to lie between the power connector and A/C compressor relay.
Please let me know your thoughts about this and if I may have missed something or what other steps I can do to verify the relay is working and if power is going to the compressor plug or not.
Thanks for reading.

 

If I recall, the lines need to be pressured up and ready to go.

 

I put refrigerant in the lines and according to the pressure guauge it's in the green however the clutch is still not spinning to take in the refrigerant and allow me to add more.

 

Is the pressure sensor working? I have not seen them go out but if the sensor is bad it would not be able to tell the ecu to signal the clutch on the compressor. I am not sure what kind of voltage it takes to kick the clutch on.

 

I'll have to check that out later. Thanks for the info! If the pressure sensor wasn't working would that cause the A/C relay to not work as well? Still confused as to why there's no clicking from the relay.

 

Yes, likely as it would never tell it to kick in. The relay might be bad as well, that does happen from time to time. I am not totally sure how you test it but there is likely a youtube video on it.

 

Did you manually put power to the compressor when adding the freon? The only way it is going to pull into the lines is either the system being in vacuum (you hooked up a vacuum pump and pulled negative vacuum in the system) or you manually jump the 30 and 87 terminals for the compressor relay to turn it on while the engine is running and you add refrigerant that way. You did the first but maybe not enough is in the system to get it to kick on. Our cars only take about 1 pound of refrigerant.

Line pressure does have to be at a certain point as well. If there is too much pressure the high side switch turns the compressor off until pressure drops and the low side returns higher.

You can also have a severe blockage in the system. Did you blow compressed air through the lines to make sure everything is flowing smoothly?

 

This, I totally assumed you pulled vac on it first. This has to be done to remove all moisture and get the new freon in. I have the harbor freight ac gauges and vac pump. They have worked well in many cars. I used it on the meds when I replaced then ac compressor.

 

I replaced both the high and low AC lines so they shouldn't be clogged. I also did Vacumm the entire system with a similar kit mentioned above prior to refilling with refrigerant. I did not manually put power to the compressor. I put freon in the car using those quick AC kits and did not do so via vaccum kit. Is that necessary? Even if I Vaccumed the system do I still need to manually power the compressor? The guauge that comes with the quick AC charge says full and almost too full.

I still have not check the AC pressure sensors on the high and low sides but will be putting 12V into the compressor later today to rule out the clutch coil.

 

Hey guys just to give you a little update:
Tried using a power probe to put 12V into the plug on the compressor to see if it would activate. To my surprise the power probe wouldn't even turn on when connecting to my battery. I then tested it out on another battery and it turned on fine. This may be a battery issue then as the battery in my car right now is a super cheap economic battery from the local auto part store. It's about 3/4 the size of a normal battery and I'm hoping it's just not powerfull enough to power the AC compressor. Will be purchasing a new battery tomorrow.

 

The car has to be running when you engage the compressor manually otherwise you're just pulling the clutch into the locked position and nothing is being compressed.

The gauge on the can you used isn't an accurate gauge. When you opened the valve on the can the vacuum in the system pulls the freon in. But it doesnt pull everything in. Once pressure is equal between the can and the low side then there is no pressure imbalance so nothing further goes into the system. You need to get the compressor activated with the car running to pull more into it.

Are you even able to start the car? If you can then your battery is good. You also dont have to go right to the compressor to activate it. You would go to the relay which is much easier to access. There will be two powers and 2 grounds. Figure out which ground side the compressor is on and apply it through there.

 

Thanks for the response! The car does start however I'm having a hard time getting the AC relay to work which is why I was suspecting an electrical issue to begin with. I've replaced the relay with a brand new one and still no clicking. (I know it could be the pressure switch still)
I know engaging the clutch with the car off doesn't pull the refrigerant in however doing it when it is off will verify if the clutch coil works or not by hearing it engage. If the clutch coil works then I can narrow the problem down to other items.

If I'm understanding you correctly your saying that I can keep attempting to put refrigerant into the system via the can and gauge method without anything bad happening? Just wanted to make sure before I do it lol.

Also the reason why I suspect my battery being a problem is because I feel like a certain amount of voltage (not sure how much) is needed to power the AC clutch on. My battery as it is able to start my car cannot power on a simple power probe which is very odd.

 

Why did all the refrigerant leak out in the first place? Apart from you pulling apart the lines?

The compressor clutch will not engage if there is too much or too little pressure in the system, that is likely why your relay isn't clicking.

The AC clutches on the second gen mazda 3s seems more reliable than the first generation, but on the first gen, they are a common issue resulting in people replacing whole compressors to remedy clutches. Have you powered the clutch on its own (attach a booster to the clutch input)? You should be able to stick a metal screw driver to the clutch surface if it is working. Engine may need to be running for this.

 

Just verified the AC clutch does work. I applied 12V to the power of it and it engaged properly.
I'm just going to replace both AC pressure switches to play it safe. Have to re-vaccum the system though. I'll let you guys know what the end result is.

 

No dont replace any switches yet. You really need to check the charge level and actual pressure on the car first.

If you don't have a set of gauges either go to a mechanic shop and pay for an Evacuate/Recharge service. They will pull the system back down and charge it to spec. If you dont have enough in the system the system wont activate. Or if you have too much the system wont activate.

 

Hey guys here's a final update: car blows cold air now.
My high pressure line popped off the other day cause I guess it wasn't completely pushed in. Was a pain to get it sealed fully. Since that happened all of the refrigerant came out so I decided to replace the lower ac pressure switch. I did what you guys suggested and added refrigerant via manifold gauge set. It worked well and was easy to do. Clutch kicked on and A/C works great.
Thanks again for all of the help guys. I appreciate it.

 

Great to hear !! Good job working through it.