AC Light Turns Off
Thread Starter
4th Gear
Joined: Jun 2021
Posts: 4
Likes: 1
AC Light Turns Off
Ok, I cannot seem to find a solution here. The AC light turns on then off. This was working just fine the last time I drove it, about 2 weeks ago. The compressor doesn't even try to turn on because the AC light turns off. I cannot tell if it is low on refrigerant if the system never turns on. I put a gauge on the port by the battery and read nothing but of course the system wasn't running. It seems to me like a sensor is bad. The external temp gauge in the car reads 85 degrees which is correct to the outside temperature so that does not seem like the problem. Any ideas?????
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,490
Likes: 3,999
From: Cape Coral, Florida
If the car is not running and it is 85 degrees outside you should see about 85 psi static pressure in the AC system if you have refrigerant in it…if you have a gauge on the system and reading zero you have no refrigerant in the system…you most likely have a leak so I would take your car to your local AC shop and let them fix it…not a DIY job for most.
Thread Starter
4th Gear
Joined: Jun 2021
Posts: 4
Likes: 1
So you are saying if I put a gauge on the port by the battery (which I believe is low pressure) I should see a reading?
Update: I hooked up the gauge to this port and turned the car on and nothing on the gauge, but then of course nothing on the AC side is running. Maybe there should always be some pressure here regardless????? Not sure.
Update: I hooked up the gauge to this port and turned the car on and nothing on the gauge, but then of course nothing on the AC side is running. Maybe there should always be some pressure here regardless????? Not sure.
Last edited by scottrappley; Jul 4, 2023 at 03:46 PM.
Melting Slicks
Joined: Jun 2017
Posts: 2,568
Likes: 1,183
From: Conyers Georgia
Yes, if you have refrigerant in the system then you will read pressure as C5Diag said. Over time a cars refrigerant will escape but there can also be a leak. You can try using a can of 134a refrigerant that comes with a gauge and charge it.
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,490
Likes: 3,999
From: Cape Coral, Florida
So you are saying if I put a gauge on the port by the battery (which I believe is low pressure) I should see a reading?
Update: I hooked up the gauge to this port and turned the car on and nothing on the gauge, but then of course nothing on the AC side is running. Maybe there should always be some pressure here regardless????? Not sure.
Update: I hooked up the gauge to this port and turned the car on and nothing on the gauge, but then of course nothing on the AC side is running. Maybe there should always be some pressure here regardless????? Not sure.
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,490
Likes: 3,999
From: Cape Coral, Florida
If you have no refrigerant you have a LEAK so the first thing that needs to be done is find the leak, evacuate the system to make sure you fixed the leak and then charge the system…you are only wasting your money charging a system that has a leak…take it to a professional !!
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Thread Starter
4th Gear
Joined: Jun 2021
Posts: 4
Likes: 1
Thanks to everyone for the help. I learned something today.
Update. I added a can of stop leak and a 12 ounce can of refrigerant and boom, the AC started working. I understand this is a band aid probably but it does get me by for now. Thanks for the help.
Update. I added a can of stop leak and a 12 ounce can of refrigerant and boom, the AC started working. I understand this is a band aid probably but it does get me by for now. Thanks for the help.
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Safety Car
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From: Orlando Florida
This is, by all means the bestest option. A seasoned pro can tell you in hour or so what's wrong and what it will take to make it right, sometimes for very reasonable money -- it could be nothing more than a bad Schrader valve leaking. Even if the diagnosis is fairly bad -- say you need a new compressor and condenser, and it's going to be $1500 -- you can decide whether you have the skill set necessary to change those parts yourself and either have the shop flush and fill or do so you yourself.
Just be aware that the path to doing it yourself is yet another tool and gadget money pit: manifold gage set, vacuum pump, etc.
Just be aware that the path to doing it yourself is yet another tool and gadget money pit: manifold gage set, vacuum pump, etc.
Race Director
Joined: Oct 2004
Posts: 12,860
Likes: 4,661
This is, by all means the bestest option. A seasoned pro can tell you in hour or so what's wrong and what it will take to make it right, sometimes for very reasonable money -- it could be nothing more than a bad Schrader valve leaking. Even if the diagnosis is fairly bad -- say you need a new compressor and condenser, and it's going to be $1500 -- you can decide whether you have the skill set necessary to change those parts yourself and either have the shop flush and fill or do so you yourself.
Just be aware that the path to doing it yourself is yet another tool and gadget money pit: manifold gage set, vacuum pump, etc.
Just be aware that the path to doing it yourself is yet another tool and gadget money pit: manifold gage set, vacuum pump, etc.
Safety Car
Joined: Mar 2017
Posts: 3,765
Likes: 938
From: Orlando Florida
Safety Car
Joined: Mar 2017
Posts: 3,765
Likes: 938
From: Orlando Florida