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AC system, compressor does not cycle

Tiny
DANIEL ADUL
  • MEMBER
  • 2001 MAZDA 626
  • 2.5L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 102,000 MILES
I was having problems with my AC system. It was blowing air but was weak. I got a pressure manifold to check the pressure and I think I inadvertently purged the Freon. So I got a vacuum pump to evacuate the AC and decided to charge the system. When attempting to charge, I could not hear the compressor kicking in. It later did after one can of 12 oz R134 Freon was added. But it was only cycling for a very short time with the condenser fan kicking in for a few seconds. In the cabin, the AC was still blowing hot. I have checked the AC compressor relay and fuse and both are good.
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Wednesday, July 4th, 2018 AT 8:21 PM

11 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,872 POSTS
Hi and thanks for using 2CarPros.com.

To be honest, if the system is low of Freon, the compressor will not engage. However, once you hit the minimum pressure, it will begin to cycle as you described. Based on what you said in your post, it sounds low on Freon. Since you have the gauges, here are a few pressures you can look for. Please keep in mind, the pressure will be affected by ambient temperatures. The hotter it is outside, the higher the pressure. And yes, you can over charge a system and it will not work properly. Here are some general pressures you should see based on outside temperatures. If the temperature you are working in isn't listed, let me know and I will be able to help you with pressures for your area and temperatures.

Ambient Temp (outside temp) Low Pressure side High Pressure Side

75 F 35 - 40psi 150 - 170psi
85 F 45 - 50psi 225 - 250psi
95 F 50 - 55psi 275 - 300psi

Here is a great link which discusses how to vacuum and recharge the air conditioning.

https://www.2carpros.com/articles/re-charge-an-air-conditioner-system

When you charge the system, once it reaches the perfect amount of Freon, the pressures should fall within these parameters. If you still have trouble, let me know.

And the fast cycling of the compressor is most likely the result of low Freon.

Let me know if this helps or if you have any questions.

Take care,
Joe
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Thursday, July 5th, 2018 AT 5:44 PM
Tiny
DANIEL ADUL
  • MEMBER
  • 7 POSTS
Hi thank you for the sound advice and prompt response. I went and got a pressure gauge manifold from AutoZone and attempted to pull vacuum. When I turned the vacuum pump on and opened the low pressure gauge valve, it only sat at 5 in Hg after forty five minutes. I tried to check, adjust, and tighten the yellow hose and still got nothing more than the 5 in Hg. I noticed the yellow valve o-rings were not in good condition; one had some tears. Even with securing the hose tight, would this be a contributor to a leak in the system when the pump is turned on? I checked the hi and low pressures without the pump and verified both are at zero.
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Thursday, July 5th, 2018 AT 11:22 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,872 POSTS
Hi again. Are you referring to the o-rings under the caps? If that is the case, they are there to help prevent leakage. The actual valve should not leak, but yes it is possible. If you are getting 0 psi readings on both the high and low sides, the system is empty and needs recharged.

If it is possible, could you send me a picture of the o-rings you are referring to so I can confirm what I am telling you?

Let me know if you have other questions. Remember, there is no such thing as a dumb question. I am here to help.

Take care,
Joe
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Friday, July 6th, 2018 AT 7:34 PM
Tiny
DANIEL ADUL
  • MEMBER
  • 7 POSTS
I went and got another pressure manifold and was able to vacuum out the ac and it held at 26 in Hg for over an hour. When I charged the refrigerant I made it up to 55 psi lol and about 350 hi. I am in Phoenix and it was about 108 degrees today. The compressor finally kicked in and it took in the refrigerant. But the car still does not blow cold air. It blows cool but not cold and the air coming out of the vent is weak. I have tried replacing the blower motor resistor before and that did not work. I am at a loss. It is properly charged but still no cold air.
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Friday, July 6th, 2018 AT 9:05 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,872 POSTS
Hi again. Since it is now operating properly and the air in the vehicle is only cool and weak, I have to question the blend air door. The blend air door is a component in the ventilation system which moves to different positions based on the temperature you want. It may not be opening fully to allow the cool air to enter the vehicle. It is located under center of the dash. I found a picture of the ac mix actuator online to help you locate it. Also, take a look through this link. It shows how to replace one.

https://www.2carpros.com/articles/replace-blend-door-motor

Let me know if this helps. As long as the compressor is running and the pressures are where they should be, this should be what is causing the problem.

Take care,
Joe
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Friday, July 6th, 2018 AT 9:34 PM
Tiny
DANIEL ADUL
  • MEMBER
  • 7 POSTS
Could you give me the specific part name for the car listed at the top of this post? I tried searching using blend door actuator and AC mix actuator and could not find anything.
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Friday, July 6th, 2018 AT 10:03 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,872 POSTS
Hi again. In my manual it is called an Air Mix Actuator. Most people refer to them as a blend air door actuator. I was able to find the OEM part number, Mazda Part - GD7A61A60, but it is discontinued. I do not know if you could find a dealer that still has one. I looked further for you and believe a company called Dorman, which is an aftermarket parts manufacturer, makes one, but I am having trouble narrowing down the one you need. You may want to contact your local parts store to see if they can identify what it is exactly. I do not want to give the wrong part number.

Let me know if this helps.

Joe
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Saturday, July 7th, 2018 AT 8:38 PM
Tiny
DANIEL ADUL
  • MEMBER
  • 7 POSTS
Okay, so I was able to get a blend door actuator from a junk yard, not the best option but like you said it is hard to get because it is a discontinued part. Anyway, I installed the new one and cycled heat-cool knob through the different options and observed the actuator arm was sweeping but still getting cool but not quite cold air. It feels like some air flow restriction but I had already tried swapping the blower motor resistor. Could that still be the issue or is there somewhere else I should be looking? Any help will be greatly appreciated.
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Sunday, July 15th, 2018 AT 12:23 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 48,345 POSTS
Is it the volume of air you are concerned with out of the vents or is it a temperature issue?
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Tuesday, July 17th, 2018 AT 2:37 PM
Tiny
DANIEL ADUL
  • MEMBER
  • 7 POSTS
The volume coming out of the vents. I have recovered the refrigerant from my AC system and charged it fully to the required specifications on the engine and verified my pressure with a mechanic here, but it is weak blowing out.
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Tuesday, July 17th, 2018 AT 4:01 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 48,345 POSTS
Some of these cars come with a cabin air filter which will plug causing the air to be blocked. But it sounds more like the mode actuator is not working right. Here is a guide to help you see what you are in for when fixing the car with diagrams for you car below:

https://www.2carpros.com/articles/replace-blend-door-motor

Airflow Mode Actuator behind lower center of dash.

Please let us know what you find.

Cheers, Ken
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Wednesday, July 18th, 2018 AT 10:05 AM

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