SOLVED! AC not working. General question, please?

[GreenBravada]

Leaving for several days of camping with the little trailer. AC is not working.

Last year, it stopped worling and I cleaned up the mating surfaces of the clutch and it worked for about a year.

When it stopped this year, I immediately suspected the clutch and installed a new one $61 at Amazon. Seems well built.

Have everything back together now, and the clutch will not stay engaged. Is it the chicken or the egg?

I have a manifold set for checking AC, but I just put a can with a gauge on because it's late.

Pressure goes up to the top of the green, drops down to practically nothing and cycles back up. When it does this, the clutch engages repeatedly but only for a second or two.

The big silver can up by the coolant tank (dryer?) has some sort of sensor or solenoid. It clicks and the clutch engages. It clicks again and the clutch disengages. Cycles every couple of seconds repeatedly.

Please give me a jump start on this one because I have to leave about noon tomorrow.

Most likely the control system, the pressure sensors or the compressor?

I'm searching FAQs and prior discussions now.

 

[movietvet]

Sounds like low on refrigerant and the low pressure cycling switch is doing it's job. You have a leak, if the refrigerant is low. Most likely culprit is usually the shrader valves.

 

[GreenBravada]

Sounds like low on refrigerant and the low pressure cycling switch is doing it's job. You have a leak, if the refrigerant is low. Most likely culprit is usually the shrader valves.

I'm not sure how it could charge up above 20 psi and then just drop to nothing unless it is a MASSIVE leak. I do think that something is either turning the compressor off or turning the clutch off. Some kind of overpressure safety valve on the compressor?

I'm wondering if the AC control system is saying the proper temp has been reached and shutting things down.

 

[movietvet]

Your a/c system cycles. A properly filled system will engage the clutch and then disengage and then reengage. Watch a you tube video and see what I am trying to tell you.

 

[GreenBravada]

This YouTube shows exactly what I am experiencing. He replaced the pressure sensing switch and solved the problem on his truck. This might be my problem because it has always seemed as if it was a safety sensor that had gone flaky. Soooo....I guess that will be what I try to find in the morning.

Thanks for the input movietvet!

 

[budwich]

I have a manifold set for checking AC, but I just put a can with a gauge on because it's late.

why are you asking for the forum to "guess" what you can easily find out by using the equipment that you got?

 

[GreenBravada]

Because I am out of time and in need of some politely offered friendly advice. I explained that in my original post. Every automotive forum has a budwich.

(Once again, thanks for the input movietvet! Much appreciated and very helpful. Friendly, even.)

 

[movietvet]

Because I am out of time and in need of some politely offered friendly advice. I explained that in my original post. Every automotive forum has a budwich.

(Once again, thanks for the input movietvet! Much appreciated and very helpful. Friendly, even.)

If it had a MASSIVE leak, the refrigerant would be all gone and the clutch would not engage at all. If the cycling switch is bad, that is an electrical protection device that also has a shrader valve behind it. If the leak is small, then the system can still have SOME refrigerant in it. On a completely full system, there is a lot of pressure and if there is a small leak it will leak faster in the beginning but as the refrigerant leaks out, the pressure diminishes/drops and the leak will be slower and slower and can even get to the point where there is not enough pressure in the system to cause the system to empty. If you are looking for leaks, look for wet spots at junction points or at the shrader valve areas. The refrigerant oil in the system will leak out with the refrigerant and that wetness gets dirt in it and it will show. If open system, replace the accumulator and the cycling switch with quality parts and while open, flush the system. Do it all, ONE TIME.

 

[GreenBravada]

If it had a MASSIVE leak, the refrigerant would be all gone and the clutch would not engage at all. If the cycling switch is bad, that is an electrical protection device that also has a shrader valve behind ...

Thanks again, Movietvet. I'll be home from a camping trip in a couple of days and will hook up my manifold gauges and see what they read. Replacing the pressure switch did not fix the problem, but it seemed to change the symptoms a little.since it was no longer dropping to zero. When I get back, I'll be able to fully look into this and try to make an evaluation. I appreciate your help when I was in a pinch the night before we had to leave. Thankfully, it was not too hot in Ohio yet, so we will survive.

 

[GreenBravada]

Just in case, asking ahead...

What are we talking about in terms of quality parts? I've seen Four Season branded parts before. Good enough? As you say, if I have to do this, I'd rather do this ONCE, but parts can be costly.

Four Seasons 83222 Accumulator with Hose​

 

[movietvet]

Just in case, asking ahead...

What are we talking about in terms of quality parts? I've seen Four Season branded parts before. Good enough? As you say, if I have to do this, I'd rather do this ONCE, but parts can be costly.

Four Seasons 83222 Accumulator with Hose​

I assume you are working on a Bravada but what is the rest of the vehicle info? I may have missed where you told us. I used to chew OP's out asap for not providing vehicle info but I have tried to be nicer about it. Tired of being nice, now. What is the damn vehicle info? OR is every single Bravada on the road, the exact same vehicle? The color "Green" is not enough.

 

[movietvet]

Use Genuine GM or AC Delco or Delphi parts, whenever available. Go to the dealer if you have to.

 

[Mooseman]

Personally, for something like the accumulator, I have no problem with Four Seizin'. It's too simple to mess up. Compressors, evaporators and condensers though I'd go with ACDelco or Delphi. But given the age of our vehicles, may no longer be available. A lot of parts have been dropped off the OEM map.

Checking on RA, GM original seems to still be available, but for a few bucks more, Four Seizin' has a full install kit available which includes seals, oil and a new orifice tube, which wouldn't be a bad idea to replace if opening the system.

More Information for FOUR SEASONS 60025SK

 

[GreenBravada]

Personally, for something like the accumulator, I have no problem with Four Seizin'. It's too simple to mess up. Compressors, evaporators and condensers though I'd go with ACDelco or Delphi. But given the age of our vehicles, may no longer be available. A lot of parts have been dropped off the OEM map.

Checking on RA, GM original seems to still be available, but for a few bucks more, Four Seizin' has a full install kit available which includes seals, oil and a new orifice tube, which wouldn't be a bad idea to replace if opening the system.

More Information for FOUR SEASONS 60025SK

I saw a "thumbs up" emoji from Movietvet and thought that was a thumbs up for Four Seasons. His next comment came later after I had ordered the what I think is the same kit you described. In fact, it just arrived as I type. It was $49 plus $11 shipping. In the meantime, I had time to put the manifold gauges on and do some testing. I think there is a leak that let out nearly all of the refrigerant. I jumpered the pressure switch and was able to load in almost two small cans of refrigerant, and now the AC is working well (until it leaks out again). I didn't want to order more parts until I found out whether or not the compressor was at least functional.

So, I must have a leak and will have to track that down. For the time being, I am going to run it and see how long it lasts. I think I have a refrigerant sniffer that I used some time ago on another car. I'll hold onto the Four Seasons kit with the accumulator, o-rings and orifice in case I end up opening up the system. I don't think I needed the new clutch I put in, but I'd had the original clutch out before, and knew it was pretty well worn and don't feel bad about that.

Movietvet, has been very helpful and got me started on this. Sometimes a guy just doesn't know enough to ask the right question and just needs to get a basic orientation, which is why the title of this post stated up front that it was just a General Question. I didn't pick up from the discussion that I was irritating Movietvet, and was grateful for the assistance he gave me, as I posted.

Sometimes, there are chronic problems specific to the platform that pop up all the time and are well known to the people who post here, and I'm trying to draw upon that knowledge rather than going through a long process. That's a shortcut, I know, but it's one of the functions of a forum like this.

One last comment is that the search function on this forum platform is not as good as it could be since it refuses to search for terms that are "too common" and removes from the search the terms like "AC" because they are too common. That's not a criticism of the forum administrators or even. I've downloaded all of the FAQs you put so much work into, but the search function doesn't always even show those in the results.

 

[GreenBravada]

I assume you are working on a Bravada but what is the rest of the vehicle info? I may have missed where you told us. I used to chew OP's out asap for not providing vehicle info but I have tried to be nicer about it. Tired of being nice, now. What is the damn vehicle info? OR is every single Bravada on the road, the exact same vehicle? The color "Green" is not enough.

Thanks for all of your help, Movietvet. You really helped me figure out what was going on. Sorry to have annoyed you. I updated my signature with basic vehicle information. My AC is functioning now, but it was extremely low on refrigerant, and I'll have to search for leaks as I go along. No obvious leaks at the three valves I can see. I believe I have a refrigerant sniffer, and I have a Four Seasons kit with accumulator, schrader valves, o-rings and the orifice. Jumpering out the pressure switch allowed me to get useful pressures and load refrigerant.

 

[movietvet]

That switch at the accumulator senses low pressure and will interrupt the current to the a/c clutch when the pressure is too low and not circulating the refrigerant oil for the moving parts in the compressor. It protects the compressor. When you jump that connector and bypass the switch, you are "going around" that switch and activating the clutch. You then allowed the system to charge with more refrigerant and move the oil and build pressure to allow the system to cool the inside. Then, you can plug the connector back on the switch and as long as the system has enough refrigerant in it and has enough pressure in it, the clutch will engage and the system will work.

The refrigerant carries the oil in the system. the refrigerant that leaks out will also leak out some of that oil, at the same time. Lots of times, the connection locations, where they are threaded together and have o-ring seals, will have wet oil and dirt and that shows the wet dirt and the leak is easy to see. With the caps off, the shraders can be leaking and even leaking at the switch at accumulator or the shrader behind where the switch threads on. The body of the compressor can leak at seals. Can be leaking at the front and the old clutch may have had wet dirt there. Worse case is the invisible evaporator in the dash. When checking for leaks at the threaded connections, always check at the bottom. The refrigerant is heavy and when leaks, it falls. To check for a leak at the evaporator, use the sniffer at the condensation drain spout at the bottom of the p/s firewall.

I have even used the old method of checking with an open propane flame and an attached hose that you held close to fittings or compressor and if flame turned green, there was the leak.

 

[GreenBravada]

That switch at the accumulator senses low pressure and will interrupt the current to the a/c clutch when the pressure is too low and not circulating the refrigerant oil for the moving parts in the compressor. It protects the compressor. When you jump that connector and bypass the switch, you are "going around" that switch and activating the clutch. You then allowed the system to charge with more refrigerant and move the oil and build pressure to allow the system to cool the inside. Then, you can plug the connector back on the switch and as long as the system has enough refrigerant in it and has enough pressure in it, the clutch will engage and the system will work.

The refrigerant carries the oil in the system. the refrigerant that leaks out will also leak out some of that oil, at the same time. Lots of times, the connection locations, where they are threaded together and have o-ring seals, will have wet oil and dirt and that shows the wet dirt and the leak is easy to see. With the caps off, the shraders can be leaking and even leaking at the switch at accumulator or the shrader behind where the switch threads on. The body of the compressor can leak at seals. Can be leaking at the front and the old clutch may have had wet dirt there. Worse case is the invisible evaporator in the dash. When checking for leaks at the threaded connections, always check at the bottom. The refrigerant is heavy and when leaks, it falls. To check for a leak at the evaporator, use the sniffer at the condensation drain spout at the bottom of the p/s firewall.

I have even used the old method of checking with an open propane flame and an attached hose that you held close to fittings or compressor and if flame turned green, there was the leak.

I also have a 1993 Volvo 940 wagon with no AC. I checked every possible exterior fitting because I know it has a leak. I have the evaporator and other needed pieces but have not replaced it yet because you have to basically pull the entire dash. I've done heater cores on several cars. The worst was a 2000 Ford Taurus where the entire dash has to come out which requires removing the steering wheel. I managed to do that with the dash in the air and the wheel still on. I'll look for leaks in the Bravada soon, but I have some rear suspension work and some welding to do on my 2000 Buick.

How do I mark this as solved (massive loss of refrigerant due to leak)? Seems I saw a place where that can be done once, but I can't find it now.

 

[movietvet]

The only way I know how to mark it solved, is like I do at other forums. May be the same here.

Since you are the OP, you go back to the first post and at the upper right, there should be a drop down spot where you open it and it will allow you to Edit Thread. Then you can go to the thread title and add the SOLVED. That is if it works the same way at this forum. Sometimes, the ability to do that will time out if the thread is old enough.

 

[GreenBravada]

This is SOLVED.

There was practically NO refrigerant in the system. Managed to recharge it, and it functions normally. Now, I have to search for the leaks.

 

[Mooseman]

And SOLVED! it is . It requires a Mod to change it.

Yeah, we know the forum's search function blows. That's why we suggest using Google's "site:" search function. You would would use it like this:

AC leak site:gmtnation.com

Google Search

And since it's Google, it will expand the search terms to AC, A/C, air conditioning, etc.

Back on the subject. If ever you do need to track down a leak, I would definitely use a sniffer. I've used mine to find leaks many times, including the evaporator. To check that with the sniffer, put the probe in the condensate drain tuba and/or the floor heater vent. Since R134a is heavier than air, it will come down into those low areas. And yes, you would need to pull the entire dash to replace it (been there, got the t-shirt )

Hopefully your leak is just a "normal" slow leak that all systems eventually have.