A/C blows cold air for a bit then back to warm air

BRIANJ2008

MEMBER
2008 HONDA CIVIC
0.8L
4 CYL
2WD
AUTOMATIC
214,848 MILES

I have been battling a A/C problem now for a bit. I haven't had A/C now for almost a year. It just one day stopped blowing cold air and blew warm air. I got a can of stuff with a gauge on it from a car part store and hoked it up and it said the pressure was good so I didn't add anything. I started watching YouTube video's and learned about the compressor and saw that the clutch was not engaging. So then I learned it could be the relay switch and they are cheap enough so I went and got one and put it in. Still nothing only warm air. So I reached down and was able to turn the face plate of the compressor. So I went back to the relay switch and changed it again. Then the clutch engaged and worked the clutch spun for about 30 seconds then stopped for 30 seconds the started spinning again the stop did this about 4 or 5 time then never spun again. While it did this I touched the low and high lines. The low line got cold to the touch and the high line didn't change at all in temp to the touch. Now what? Is this a charging issue? Am I over looking something?

1 Reply

JACOBANDNICKOLAS

MECHANIC
109,896 POSTS

Welcome to 2CarPros.

Before I get started, here is a link that discusses the most common causes of the AC not working, how to identify the issue, and how to repair it.

https://www.2carpros.com/articles/car-air-conditioner-not-working-or-is-weak

Next, you mentioned that the second time you replaced the relay, it worked for a short time. Confirm the connectors in the relay box are clean, not corroded, and not pushed in so as not to make connection with the relay.

This could be a power issue, freon level issue, or a faulty compressor clutch. There are two things we need to do. First, I need you to test if the AC compressor is actually getting power when you turn it on and the compressor itself. First, check for continuity between the A/C compressor clutch connector No. 1 and No. 3. If there is no continuity, replace the thermal protector. See pic 1.

NOTE: The thermal protector will have no continuity above about 252 to 262 °C (122 to 128 °C). When the temperature drops below about 241 to 219 °F (116 to 104 °C), the thermal protector will have continuity.

Next, I need you to disconnect the field coil connector (A in pic 2). Check resistance of the field coil. If resistance is not within specifications, replace the field coil. Resistance is indicated in the pic.

You will need to use a multi meter to test. Here are a few links that may help.

https://www.2carpros.com/articles/how-to-check-wiring

https://www.2carpros.com/articles/how-to-use-a-voltmeter

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

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If that checks out to be in spec, confirm there is a power supply to the compressor.

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If power is present but the compressor doesn't engage, chances are you are still low on freon. What needs to be done is to check both high and low side pressures using an AC manifold gauge set. Here is a link showing them being use. I will need to know what the pressure is and the outside temperature when tested.

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

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

Take care,
Joe

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