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Discussion Starter #1 (Edited)
The AC is on but it's not blowing cold air. The air that comes out with the AC on is not noticeably colder than with the AC off. I bought one of those AC refill kits - it came with a gauge that showed around 35psi and according to the kit it should've been 45 - 55 psi, so I recharged (it was 134a gas), but no improvement.
Any ideas how to troubleshoot the AC? How can I check if it's even working? Any fuses I should check?
The refill valve is on the top left side of the engine compartment right?
 

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Check the AC magnetic clutch relay under the hood in the fuse box and swap it with the horn relay. Your system may now be overcharged. Does the AC light come on when you hit the button?
 

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Discussion Starter #3
The light does come on. It might indeed be overcharged, what's the recommended reading for that?
 

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25-40 psi on the low side and 200-250 on the high side, depending on the outside temp. Your low side was at the correct pressure to start with. High should be 2.5 times the outside temp. This is with the engine running at 1500 RPM. Did you try swapping the MG CLT (AC)relay with the horn or fog relay? Is the compressor cycling? It is now overcharged.
 

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Discussion Starter #5
I was able to fix the problem.
I checked all the fuses under the hood - everything was OK. (Which one is the AC and which one is the horn one by the way?) I touched the low end aluminum line that goes inside the the car and it was noticeably cold. That made me think that the compressor is working, so I took the glove compartment out in order to check the heater core.
As I was looking around there I noticed the little plastic cover for the cabin filter. I pulled it out - I never seen a filter that dirty! There were leafs, dead bugs etc etc...
I bought the car about 1.5 years ago, but my wife has driven it only about 10k miles. I wanted to replace the cabin filter (I did replace the air filter) but I couldn't find it. I decided it's not a big deal and I'll check online and change it at a later time. Unfortunately I never got around to it. I think it hasn't been changed in at least 40k - 50k miles, if ever :facepalm:

Anyhow, I pulled it off and voila the AC started working ... :clap:
I noticed a quite loud noise when the AC is running, so I let out some of the gas out, I guess I overcharged it :ugh3:

Very unlikely problem isn't it?

I'm thinking to put a piece of AC insulation over the aluminum line that goes inside the car to preserve more of that cold air. Is there a reason not to do that?

Thanks for the help :chug:
 

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I was able to fix the problem.
I checked all the fuses under the hood - everything was OK. (Which one is the AC and which one is the horn one by the way?) I touched the low end aluminum line that goes inside the the car and it was noticeably cold. That made me think that the compressor is working, so I took the glove compartment out in order to check the heater core.
As I was looking around there I noticed the little plastic cover for the cabin filter. I pulled it out - I never seen a filter that dirty! There were leafs, dead bugs etc etc...
I bought the car about 1.5 years ago, but my wife has driven it only about 10k miles. I wanted to replace the cabin filter (I did replace the air filter) but I couldn't find it. I decided it's not a big deal and I'll check online and change it at a later time. Unfortunately I never got around to it. I think it hasn't been changed in at least 40k - 50k miles, if ever :facepalm:

Anyhow, I pulled it off and voila the AC started working ... :clap:
I noticed a quite loud noise when the AC is running, so I let out some of the gas out, I guess I overcharged it :ugh3:

Very unlikely problem isn't it?

I'm thinking to put a piece of AC insulation over the aluminum line that goes inside the car to preserve more of that cold air. Is there a reason not to do that?

Thanks for the help :chug:
Glad it was an easy fix. I put pipe insulation over my low line to help insulate it, but I did not put it on the metal part of the line, just the rubber. My fear is that the pipe insulation will hold water when the low line sweats and have no where to go and eventually rot the line.
 

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You siad there was a 40 amp fuse under the dash?? where?? I'm having the same problem. A/c suddenly stopped working. Clutch will not engage. Already had the low pressure switch replaced but did not help. There is plenty of freon in the system. Hoping my problem is as simple as yours was.
 

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I'm having a similar problem with a recently acquired 03 S. Previous owner claims he changed the compressor recently and may have overcharged it but isn't sure..... low side consistently reads low around 25 and high side roads around 200-215 (82* ambient temp). Poking around the internet that seems to be an evaporator and/or expansion valve issue? Not a quick job to get to it would seem. Cant seem to find the dryer on this vehicle, anyone have a diagram or pic?

Edit: adding more details for context:

A/C blows warm at low speed, somewhat cool at highway, colder on low fan speed than high fan speed, and also colder on the right side vents than the left... (blend door motor?). Compressor engages as normal. Changed cabin filter, was horrendous. Swapped horn and a/c relay just to check, didnt change anything. A/c light in the button does come on.
 

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Cant seem to find the dryer on this vehicle, anyone have a diagram or pic?
Here is the drier location zoomed out and zoomed in. It is integral to the condenser and takes up almost the whole vertical space on the driver's side. Circled in yellow and with yellow arrows:



 

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Cant seem to find the dryer on this vehicle, anyone have a diagram or pic?
Here is the drier location zoomed out and zoomed in. It is integral to the condenser and takes up almost the whole vertical space on the driver's side. Circled in yellow and with yellow arrows:



Should I do a leak test before jumping to the replacing the evap?
 

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low side consistently reads low around 25 and high side roads around 200-215 (82* ambient temp). Poking around the internet that seems to be an evaporator and/or expansion valve issue?
Should I do a leak test before jumping to the replacing the evap?
According to one chart, at 82F the low pressure side should be around 40-55 psi. The high pressure side should be 175F-210F for 80F ambient temp. For 85F ambient temp the high pressure side should be 225F-250F. Your ambient temp is 82F, so a high pressure side psi of 200-215 seems to be "normal" to me.


I'm looking at a different chart, which shows different numbers compared to above. The humidity rate is also a factor. I can't access my Toyota factory service manual until late tonight, so I don't know which chart is accurate, but I'd say now that I think you're a little undercharged. You might have moisture in the system if the person who installed the compressor did not run a vacuum on the system for at least 30-60 minutes.


Have you added refrigerant to bring it up to 40 psi if the ambient temp is 82F? Some would say to evacuate the whole system, run a vacuum for a certain period of time to see if there's a leak, and if no leak, then recharge with the correct amount of refrigerant.
 

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low side consistently reads low around 25 and high side roads around 200-215 (82* ambient temp). Poking around the internet that seems to be an evaporator and/or expansion valve issue?
Should I do a leak test before jumping to the replacing the evap?
According to one chart, at 82F the low pressure side should be around 40-55 psi. The high pressure side should be 175F-210F for 80F ambient temp. For 85F ambient temp the high pressure side should be 225F-250F. Your ambient temp is 82F, so a high pressure side psi of 200-215 seems to be "normal" to me.


I'm looking at a different chart, which shows different numbers compared to above. The humidity rate is also a factor. I can't access my Toyota factory service manual until late tonight, so I don't know which chart is accurate, but I'd say now that I think you're a little undercharged. You might have moisture in the system if the person who installed the compressor did not run a vacuum on the system for at least 30-60 minutes.


Have you added refrigerant to bring it up to 40 psi if the ambient temp is 82F? Some would say to evacuate the whole system, run a vacuum for a certain period of time to see if there's a leak, and if no leak, then recharge with the correct amount of refrigerant.
Yes, I should have included that we added multiple cans of refrigerant and it seems to only build up pressure on the high side and not the low side. After we put in 2 cans, it seemed overcharged because the compressor would stop and if we forced the compressor on (via connecting a wire directly from the plug to the battery terminal) it would force refrigerant out somewhere (sounded like a paintball gun when it runs out of air). We had not bought a dual gauge kit yet by that point, and could only measure low side with the gauge on the refrigerant dispenser on low side. After we purged pressure out of the high side, the compressor began cycling back on as usual.

In addition to my question about doing a leak test, is there some kind of cleaning product that should be tried first? I saw a YouTube vid with a lot of views say that cleaning kits were a waste of time due to how small the passageways are on modern condensers and evap.
 

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In addition to my question about doing a leak test, is there some kind of cleaning product that should be tried first? I saw a YouTube vid with a lot of views say that cleaning kits were a waste of time due to how small the passageways are on modern condensers and evap.
Why do you think cleaning is necessary? Did the previous owner say that there was that black debris in the lines? Did the previous owner say that the original compressor had seized?
When I replaced my compressor, I used denatured alcohol to flush the lines out, but it probably wasn't necessary because I didn't have any debris in the lines which can be caused by a seized compressor, which I did not have. Yes, I've heard that if there was debris in the lines, that the condenser could be plugged up/partially plugged up and that it's difficult to clean that out, requiring replacement of the condenser. Denso condensers are not expensive online, btw, but you need to determine if that is even necessary.

If the refrigerant is evacuated, you can pull a vacuum on the system and let it sit for a number of hours to see if the vacuum gauge drops. If it doesn't drop, then there are no leaks. Another way to determine leaks is to install a dye into the system and use a black light with those special yellow glasses to find a leak. There is also an electronic device that can detect leaks.

According to the factory repair manual, the total system charge is 17.28 oz +/- 1.06 oz of refrigerant. In other words it should be between 16.22 oz - 18.34 oz of refrigerant. I can not find a chart in the factory repair manual showing appropriate pressures based on ambient temperatures and humidity. The repair manual does list an A/C pressure gauge set as a recommended tool, but I can't find anywhere in the manual that shows actually using the tool. I believe the reason is that the repair manual advocates evacuating the system and charging with the correct amount of refrigerant (shown above). With this correct amount of refrigerant, there is little need to worry about the pressures (assuming all the A/C components are in good working order). The pressures do indicate the operating condition of the system, though, which is one of the reasons people use them to decide what to do (add or remove refrigerant, repair/replace certain components, etc.). The repair manual has many, many pages, so perhaps I've missed a page, but not as far as I know.
 

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The reason I'm asking about using a cleaner is because changing the Evap is like an 8hr job on a good day (https://youtu.be/GfJ2NFNHuDE) and if I can avoid doing it by cleaning the evap with a cleaner, that would save me a lot of time and headache.
 

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The reason I'm asking about using a cleaner is because changing the Evap is like an 8hr job on a good day (https://youtu.be/GfJ2NFNHuDE) and if I can avoid doing it by cleaning the evap with a cleaner, that would save me a lot of time and headache.
You first have to determine if the evaporative coil even needs to be replaced or cleaned. I'm not sure, but I don't think you can flush clean the evap coil without removing the expansion valve. The expansion valve might stop the flushing of the evap coil from happening. Perhaps someone else reading this thread can shed some light on that. When I replaced my compressor, I didn't mess with the evap coil or expansion valve. Yes, removing that evap coil is a big job from what I understand. I've only done that once, and it was on a Gen 3 Camry. It became a massive pain starting with the Gen 5 Camry (or Gen 4?). Gen 9 Corolla also a pain from what I understand.
 

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It was my understanding that low LP side pressure and average HP pressure meant bad evap
A chart I looked at showed that the expansion valve could be compromised if the high pressure side was too high, but didn't cover the scenario you have. Hopefully someone can chip in some info here. I'd hate to see you tear into that only to discover it was fine.
 

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Just cool... not cold.... damn. foolish me I thought because it was dripping that was a sign that it was cooling and refrigerating at some point. This is my first time getting into the weeds with a/c.

What would you do next if you were me?
 

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Many ways to skin this cat..
My 1st guess would be a failed expansion valve. While in there I'd change the desiccant pack, all o-rings, schrader valves & add a couple ounces of pag oil. Be on the lookout for debris throughout. Depending on how much debris (if any) there was and how much money I wanted to spend I'd do a minimum of a flush & oil replacement with possibly condenser & finally compressor replacement.

As far as DIY goes I'd start with a visual inspection (oily spots/hose cracks) and go over it with gas leak detector (bubbles) to leak check. If you have a temp gun to use on the condenser I'd check it while running for a spot with a sudden temp drop indicating a restriction there. If nothing obvious, have refrigerant recovered at a shop & make sure they weigh it to add to the clues before digging in.
 
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