General AC Troubleshooting and Repair

[whynotthinkwhynot]

Aironjack- thanks, I'll make a note of that. Apparently my understanding of the operation of the AC system was a little backwards according to that diagram. I can't rely on all the people who have told me things in the past.

1) Refrigerant goes in through the low pressure port located in the passenger fender under the plastic inner fender well just behind the headlight. I thought I explained that well enough in the recharging section.
2) I can rearrange that so that you'd start checking at the relay if that's not how I wrote it. Yes you should start at the beginning in electrical testing. Pin 86 on the AC relay should have power to ground, power on one side of the relay, if no power check fuse. As long as pin 86 on the AC relay has power, then the rest of the electrical control system is good. That would be a more concise test than the way I wrote it.
3) Ok.
4) If you have the system down to remove the orifice tube, then it should be replaced regardless. The orifice tube traps debris, usually metal shavings from the compressor, and prevents it from reaching other areas of the system.
5) If you're following my directions, then once you reach the vacuuming stage the system will have been discharged a long time ago. As I wrote at the very start, that tutorial is for people who have AC system leaks, not for people who have a charge. I've been trying to add things for people who have charged systems that aren't working, like how to tell your compressor is bad with gauges, to complete the explanations. As for anything else, the vacuuming might leave a small amount of oil somewhere in the system, but that's about it. Any moisture will be gone along with any leftover refrigerant. Nobody here can afford to buy a reclamation machine, and yes, if anyone has a charged system that needs repair, I need to put in there that they should go visit a friendly lube or AC shop that will suck up your refrigerant for free. They will reuse it, and charge someone else- so don't let them charge you to remove it.

Yeah, I figured that could be the wrong name for the accumulator. I should've looked it up first, but I wrote all this on the fly. I'm surprised I wasn't corrected sooner. Like Bluefront said, the receiver/dryer/expansion valve system and the accumulator system work much the same way for the shadetree. It's just another spot to change O-rings when the system is down (depressurized). Be thankful we only have O-rings to replace. You want real AC fun, go work on a Chrysler. Not sure about DSM, I avoid Mitsus, and their Chrysler variants like a plague.

Thanks for adding the videos, that will surely help those who can watch the vids.

Bluefront, I have no idea what I'm going to do about 56k users. If I add pictures, then that screws 56k, yet pictures are a great help. I might have to do two, one 56k approved, and one that is full of pics. Not that 56k would never load a thread with pics, but you should at least be forewarned so that you can go get some coffee, popcorn, etc.

There's a lot to these silly AC systems although most people will survive by just knowing how to replace O-rings and recharge. I just recently did my old work van, and showed my business partner how simple it was.

[whynotthinkwhynot]

Aironjack- thanks, I'll make a note of that. Apparently my understanding of the operation of the AC system was a little backwards according to that diagram. I can't rely on all the people who have told me things in the past.

1) Refrigerant goes in through the low pressure port located in the passenger fender under the plastic inner fender well just behind the headlight. I thought I explained that well enough in the recharging section.
2) I can rearrange that so that you'd start checking at the relay if that's not how I wrote it. Yes you should start at the beginning in electrical testing. Pin 86 on the AC relay should have power to ground, power on one side of the relay, if no power check fuse. As long as pin 86 on the AC relay has power, then the rest of the electrical control system is good. That would be a more concise test than the way I wrote it.
3) Ok.
4) If you have the system down to remove the orifice tube, then it should be replaced regardless. The orifice tube traps debris, usually metal shavings from the compressor, and prevents it from reaching other areas of the system.
5) If you're following my directions, then once you reach the vacuuming stage the system will have been discharged a long time ago. As I wrote at the very start, that tutorial is for people who have AC system leaks, not for people who have a charge. I've been trying to add things for people who have charged systems that aren't working, like how to tell your compressor is bad with gauges, to complete the explanations. As for anything else, the vacuuming might leave a small amount of oil somewhere in the system, but that's about it. Any moisture will be gone along with any leftover refrigerant. Nobody here can afford to buy a reclamation machine, and yes, if anyone has a charged system that needs repair, I need to put in there that they should go visit a friendly lube or AC shop that will suck up your refrigerant for free. They will reuse it, and charge someone else- so don't let them charge you to remove it.

Yeah, I figured that could be the wrong name for the accumulator. I should've looked it up first, but I wrote all this on the fly. I'm surprised I wasn't corrected sooner. Like Bluefront said, the receiver/dryer/expansion valve system and the accumulator system work much the same way for the shadetree. It's just another spot to change O-rings when the system is down (depressurized). Be thankful we only have O-rings to replace. You want real AC fun, go work on a Chrysler. Not sure about DSM, I avoid Mitsus, and their Chrysler variants like a plague.

Thanks for adding the videos, that will surely help those who can watch the vids.

Bluefront, I have no idea what I'm going to do about 56k users. If I add pictures, then that screws 56k, yet pictures are a great help. I might have to do two, one 56k approved, and one that is full of pics. Not that 56k would never load a thread with pics, but you should at least be forewarned so that you can go get some coffee, popcorn, etc.

There's a lot to these silly AC systems although most people will survive by just knowing how to replace O-rings and recharge. I just recently did my old work van, and showed my business partner how simple it was.

[bluefront]

Regarding dial-up users and pictures......AFAIC, there is no reason these sorts of pictures need to be hi-resolution. It's not like anybody is going to print out a big picture of a can of r134. A 50k-100k photo will show up plenty good on every monitor....just don't zoom in too far.

I've up-loaded hundreds of photos this size, and down-loaded them also with a dial-up. What really irritates me though, is to wait for a long time while some dumb 2mb photo of a tire down-loads. Resizing a photo to a manageable size is very easy..... Photos for the picture gallery are another matter.

Rant over....

[bluefront]

Gauge readings.......many of the cans of refrigerant come with a low-side pressure gauge. Usually that's all you need, and I assume they also come with some explanation of the pressure readings.

Basically.....these readings from both a hi-side and low-side gauge set are a lot like a CEL. They just give you something to go by, since there's no absolute reading that's correct all the time. If you hook up both gauges without the engine running, the readings are about equal. And the exact numbers depend on the ambient temperature.

As soon as you start the engine and the compressor kicks in, the low-side will go down, and the high-side will go up. (if everything is working correctly). On a day with the outside temperature of around 75F, with the engine idling, the low side will read about 30-40lbs (while the compressor is running). At the same time the high-side will read around 150-170lbs. Remember these readings are temperature-dependent.On a hot day the high side can go much higher.

So when you watch the gauges, you can tell if something is wrong. For instance....if you see a hi-side reading of 350lbs on a cool day, it can mean the system is over-charged with refrigerant. Or if the low side reading goes down to almost 0 lbs, it can mean you're almost out of refrigerant, but it could also mean a block in an expansion valve.

There are many examples of these sorts of readings, and some can be tough to figure. So reading up on the subject can be helpful for trouble-shooting.

The other use for the high-side port.....recharging the system without the engine running. You can turn the can of refrigerant up-side-down, and charge the system with liquid refrigerant. It goes in much faster that way. I'm sure there are other uses.....

Never.....open up the high-side valve on a set of gauges with the engine running. the pressure will push refrigerant back into an empty can, and is very dangerous.

Always wear eye protection....without fail.

[aironjack]

Hi guys,

The AC system is pretty complex and some repairs can be done by anyone with little time and others take more time and knowledge.

I think it would be a good idea to extend the manual to all sort of repairs, not only leaks. I am a 100% sure my issue with the AC is that it is clogged somewhere. Of course, some people will never do a whole AC system, but I wouldn't have any issue on doing such a project and I think some people would like to have the information on how to do it, besides the amount of money you can save.

The AC is a mechanical system controlled electronically as we all know. I think it would be good to state this in the beginning of the tutorial. The electric part of the system is easier to diagnose and cheap to fix if a switch, relay or fuse were damaged.

The reason I bought AC gauges is because this way you can know a lot more about what the system problems can be in the mechanical side, which is pressure oriented as we know. I found a very good pdf explaining how to interpret the gauges:

AC gauges troubleshooting:
http://www.manexcorp.com/images/Bus_Guage_TS.pdf

I believe that the main tools for fixing ACs are:

• - These gauges, that go from 50 to a 150 dollars depending on the brand. I got them used and in good quality for 40$.
• - The UV light and glasses for finding leaks or a sniffer, that can be loaned in many auto stores.
• - A multimeter to test current and continuity in the different parts of the electric system.
• - A repair manual for knowing the details of your system and having access to the wiring diagrams of the AC.

In your explanation it looked like you were discharging the system vacuuming and that's why I asked. I didn't have heard of anything like that before. But now I understand you were referring to cleaning the AC lines.

I forgot some people don't have DSL connections. But on the other hand, I think having video material and a lot more pictures would be very helpful, always small size too. From my point of view, it is impossible to understand the AC without seeing it.

And the exact numbers depend on the ambient temperature.

And also on the humidity.

If you have the system down to remove the orifice tube, then it should be replaced regardless. The orifice tube traps debris, usually metal shavings from the compressor, and prevents it from reaching other areas of the system.

Totally true. What I meant is that the orifice tube gives you a picture of the health of your AC system and if you need to chemically flush the system or not.

I think understanding how a system works is crucial for troubleshooting and fixing it. The AC system can be explained in very detail using complex terms, but your explanations are easy to follow. Keeping it simple is a good idea.

'm sorry but I didn't take the time to research before I wrote. I have a lot going on here with a business, a baby, and a wife who can't drive right now. I spend too much time on here right now, and need to be spending more time on my business writing up a web page for us. It will take some time to get everything ironed out, and that's why I haven't contacted S2 to put this in the Complete How-To just yet. It's still a work in progress IMO.

You don't have to be sorry. I am just trying to help to make it better and correct some mistakes, I wouldn't have done it better than you.
If you need help writing on anything or whatever let me know.

I hope this information helps

[aironjack]

Hi everyone,

Here come the pictures. I was replacing my fender, which was badly dented. So I took advantage to take some pictures.

I have been troubleshooting my electrical system. Everything was working correctly. I hooked my pressure gauges reading 0 psi on both sides: high pressure and low pressure. So the system is empty of refrigerant. I am going to bridge the low pressure switch to charge it and look for leaks. I don't have a vacuum pump, if so I would do a deep vacuum to see how it holds vacuum. If anyone knows where can I rent or loan one, that would be good.

Anyways, here are the pictures.

Picture of the compressor and the lines coming out of the discharge and suction ports:



Picture of the connector that goes to the clutch of the compressor.



Picture of the accumulator from underneath it. The red switch is the high pressure cut-off switch that I removed for troubleshooting.



Picture of the low pressure cut-off switch. It took me around 30 minutes to find it and it is very hard to reach.






Picture of the AC lines going to the accumulator on one side and going through the hood by a hole on the other:



Picture of the accumulator and the high pressure switch trough the "transparent" fender:



Picture of my pressure gauges connected. The blue hose goes to the low pressure port on the accumulator:






I had to ask in a specialized ac forum to find the high pressure port. I was looking for it on the compressor or in a high pressure line near it. It turned out to be on the condenser. I will take a picture tomorrow.

Tomorrow I will be posting the details of my AC, they are on a sticker in the hood.

I hope it helps

[whynotthinkwhynot]

Oh, about what Bluefront said about how some things won't really matter to the end user, I think I will edit what I wrote over time to make it less technical and lean more to the average person's understanding of the AC system. Most people will only need to know how to replace O rings, parts like the accumulator and orifice tube, vacuum testing, and recharging. You don't really need to know how it works to service it.

I would like some more information from someone who knows firsthand what the high pressure port is for. The only use I know for it is to test the compressor's operation, but I'm sure it can be important for diagnosing something else. For those with leaks, the high pressure port is not really needed which is why I didn't get into it or it's location- which I don't really know right now when I'm writing this.

I'm sorry but I didn't take the time to research before I wrote. I have a lot going on here with a business, a baby, and a wife who can't drive right now. I spend too much time on here right now, and need to be spending more time on my business writing up a web page for us. It will take some time to get everything ironed out, and that's why I haven't contacted S2 to put this in the Complete How-To just yet. It's still a work in progress IMO.

[whynotthinkwhynot]

Oh, about what Bluefront said about how some things won't really matter to the end user, I think I will edit what I wrote over time to make it less technical and lean more to the average person's understanding of the AC system. Most people will only need to know how to replace O rings, parts like the accumulator and orifice tube, vacuum testing, and recharging. You don't really need to know how it works to service it.

I would like some more information from someone who knows firsthand what the high pressure port is for. The only use I know for it is to test the compressor's operation, but I'm sure it can be important for diagnosing something else. For those with leaks, the high pressure port is not really needed which is why I didn't get into it or it's location- which I don't really know right now when I'm writing this.

I'm sorry but I didn't take the time to research before I wrote. I have a lot going on here with a business, a baby, and a wife who can't drive right now. I spend too much time on here right now, and need to be spending more time on my business writing up a web page for us. It will take some time to get everything ironed out, and that's why I haven't contacted S2 to put this in the Complete How-To just yet. It's still a work in progress IMO.

[whynotthinkwhynot]

Thanks guys!!! The pics are great, I have to get back to work on this thread so I can complete it, but those pics are a great help!! Hopefully I can download and edit the big ones to a smaller size and then put them on the FF pic server.

It's quite retarded that Ford would hide the LP port, and make the HP port easily accessible. WTF were they thinking?

Wait, I know, more of manufacturers trying to keep people from working on their cars- it's easy to reach the LP with the car on a lift.

[Raider]

Double post. Sorry.

[Raider]

Some additions to consider:

Orifice tube is a metering device. The restriction creates the low pressure needed to feel cool. With r12 it was almost a 1:1 ratio, 35psi was equal to about 35 degrees, you almost never saw this at the vent but would aim for a 35 degree below ambient temperature at vent.

High side: Important for checking for excessively high pressures, usually a blockage in the system. (Orifice)

Oil: alternate advantage to vacuum system. Measure out replacement oil and suck it up the fill line before attaching freon.

Leak checking: Beware that just because you lost vacuum does not cinch that you have a leak. Did you replace the desiccant? The accumulator has a material in it to suck the moister out of the system. Pulling a vacuum caused the water to boil, you need to pull vacuum for a while(Longer the better) to boil all the moister out (especially if you reused the accumulator or left the new one open for long). When filling, only fill enough to raise pressure to ambient temp. If it is 90 outside, the low side should show 90 psi(roughly). This is more than enough pressure to test the "Low side" for leaks and feel confident you do or don't have any. In addition to dyed oil, I like to use a soapy solution. Spray all connections and bubbles indicate a leak.

Reason for high side being easy to access - Production! It is easier to pressure fill from the high side during assembly.

BTW - Nice work!

[miragesmack]

Great thread. I just pickep up a 2000 Sony Edition. A/C does not work, compressor does not come on. Found many great tips in this thread. I especially like the "warm water" to force refrigerant into system. Nice! Once I confirm my electrical is all fine, I'll go there.

I hope I can do it with only the 2 low speeds of my fan, high doesn't work. I replaced my blower motor resistor, hoping that would give me my top 2 speeds, but it was not to be. I guess it's the fan control itself.

Anyway, great thread. Will keeps tabs on it for sure.