2002 A/C intermittently not working

[NickTbird]

My A/C seems to have a mind of its own and intermittently works. I brought it to the shop last week and it appeared to be slightly low on refrigerant and was working better after the recharge, however two days later it was not working intermittently again. It doesn't seem to have a pattern, (ie. highway, cold vs hot days, humidity, after a hard acceleration), it just has a mind of its own. When it isn't working the A/C clutch engages then immediately disengages. Bringing it back to the shop today for them to test things, but I wanted to post here to see if anyone had the same issue.

Moderator Note: 2021- This thread has the diagram and troubleshooting- https://forums.fordthunderbirdforum...ne-side-2002-2003-2004-2005-thunderbird.9446/

 

[suzukiridr]

I have the same issues as you have. Replaced the 5 port DCCV, and no help. Had a shop evacuate system, and reservice, weeks later returned to shop and was told freon was low. Added freon, and was good for another week or so. After reading forum, it seems the O rings go bad and bypass freon, so the compressor has to be replaced. Mine was replaced about 8 years ago, and I guess is due again. Read the blogs, it seems to be a common problem (one of many) with these cars.

 

[NickTbird]

I will have them check the refrigerant levels again, but I don't suspect them to be low, even before they recharged it, they didn't think it was low enough to cause the issue but worth a try.

 

[suzukiridr]

If I press in on the high pressure port of the system (engine off) I always get a release of freon, but there is not enough in the system to cool the car. Always need to add a can to top it off. I wish the low port was easier to get to.

 

[David S]

My A/C seems to have a mind of its own and intermittently works. I brought it to the shop last week and it appeared to be slightly low on refrigerant and was working better after the recharge, however two days later it was not working intermittently again. It doesn't seem to have a pattern, (ie. highway, cold vs hot days, humidity, after a hard acceleration), it just has a mind of its own. When it isn't working the A/C clutch engages then immediately disengages. Bringing it back to the shop today for them to test things, but I wanted to post here to see if anyone had the same issue.

Mine needed compressor and an expensive hose. (they where really bad, no B. S.) Dealership did it for $1300. Several months and still good.

 

[The Flash]

If you do not understand the A/C system don't mess with it.

The first thing that must be done with an A/C system is to check the low and high pressures with a set of gauges.

Pressing on the pressure fittings and releasing freon is a fool's test.

 

[NickTbird]

Mine needed compressor and an expensive hose. (they where really bad, no B. S.) Dealership did it for $1300. Several months and still good.

Did you have the same intermittent issue with it working on and off, even on the same day?

I just took it to the shop, it worked right after start up, stopped a few minute later for about 5 minutes, then came back for 1 minute then stopped. After they hooked up the gauges and started it up it worked amazingly and for most of the trip back to work before having issues again. No issue with the refrigerant levels, they referred me to a shop that specifically works on A/C systems and that shop is thinking the simplest things are the switch that engages the clutch or the pressure switch(es). From how he described where the clutch switch is located, it would have likely been replaced with your compressor. Hoping it is one of those switches and not the compressor, climate control module or the other module that control the A/C system. I have read that the climate control module can be the culprit for something like this as well.

If you do not understand the A/C system don't mess with it.

The first thing that must be done with an A/C system is to check the low and high pressures with a set of gauges.

Pressing on the pressure fittings and releasing freon is a fool's test.

Agreed. I like to fix my own stuff, but I wouldn't mess with an A/C system, unless it comes down to the modules.

Checking for refrigerant by pressing the fittings wouldn't tell you anything meaningful anyway - just that there is something in there, which was already known since it works sometimes.

 

[312]

My A/C seems to have a mind of its own and intermittently works. I brought it to the shop last week and it appeared to be slightly low on refrigerant and was working better after the recharge, however two days later it was not working intermittently again. It doesn't seem to have a pattern, (ie. highway, cold vs hot days, humidity, after a hard acceleration), it just has a mind of its own. When it isn't working the A/C clutch engages then immediately disengages. Bringing it back to the shop today for them to test things, but I wanted to post here to see if anyone had the same issue.

If they charged it correctly it sounds like a defective low pressure switch. Could also be you have a leak and are loosing refrigerant , but the fact that it works ok and then does not and the short cycling of the a/c clutch indicates a bad low pressure switch. (short cycling)This part is replaceable if you are handy without opening the system . It has a plug on it and screws into a fitting which has a Schrader valve in it to prevent refrigerant loss.

 

[NickTbird]

If they charged it correctly it sounds like a defective low pressure switch. Could also be you have a leak and are loosing refrigerant , but the fact that it works ok and then does not and the short cycling of the a/c clutch indicates a bad low pressure switch. (short cycling)This part is replaceable if you are handy without opening the system . It has a plug on it and screws into a fitting which has a Schrader valve in it to prevent refrigerant loss.

Thank you for the info, I assumed it would open the system if I replaced that. Do you happen to know the part number? I will look it up, but I had a hard time finding it before. It is the one on the driver side about 4-5inches below the radiator support, correct?

Edit: Looks like I found it, and I can see the "pin" that opens the schrader valve.

Ordered a new low pressure switch. I had a feeling it is the switch specifically because of the short cycling, but couldn't find anyone on the forum that had this issue especially intermittently; at the same time nothing makes sense to be intermittent. If it fixes it, I saved on the shop time to diagnose it, if it isn't then I guess I have a nice new switch... and a backup switch on hand.

 

[312]

Thank you for the info, I assumed it would open the system if I replaced that. Do you happen to know the part number? I will look it up, but I had a hard time finding it before. It is the one on the driver side about 4-5inches below the radiator support, correct?

Edit: Looks like I found it, and I can see the "pin" that opens the schrader valve.

Ordered a new low pressure switch. I had a feeling it is the switch specifically because of the short cycling, but couldn't find anyone on the forum that had this issue especially intermittently; at the same time nothing makes sense to be intermittent. If it fixes it, I saved on the shop time to diagnose it, if it isn't then I guess I have a nice new switch... and a backup switch on hand.

If you had a metering device in the evaporator that was not opening when it should , that too could cause this.I am assuming you don't have gauges so i gave you the easy fix . If the evaporator metering device was working intermittently , you would see the low side pressure drop below the low pressure switch cut out setting and cycle the compressor clutch. Good luck Hope it works out for you.

 

[NickTbird]

If you had a metering device in the evaporator that was not opening when it should , that too could cause this.I am assuming you don't have gauges so i gave you the easy fix . If the evaporator metering device was working intermittently , you would see the low side pressure drop below the low pressure switch cut out setting and cycle the compressor clutch. Good luck Hope it works out for you.

Thank you for the information.

I do not have gauges and unfortunately every time I brought it to the shop it started working, so I don't know what the gauges show when it isn't working right. I am not sure if this is normal, but after pulling the car into the shop with the A/C not working, they shut it down and then connected the gauges; the low side was maxed out on the gauges until they turned the car on again and it went down to the normal range.

I think my capabilities on fixing this are limited to the switch, now that I know there is a schrader valve behind it. I am going on vacation for a week and hoping this does the trick so I have A/C on my trip during a heat wave. Local shop that specializes in A/C is booked for 2 weeks.

 

[mrmanly]

Thank you for the information.

I do not have gauges and unfortunately every time I brought it to the shop it started working, so I don't know what the gauges show when it isn't working right. I am not sure if this is normal, but after pulling the car into the shop with the A/C not working, they shut it down and then connected the gauges; the low side was maxed out on the gauges until they turned the car on again and it went down to the normal range.

I think my capabilities on fixing this are limited to the switch, now that I know there is a schrader valve behind it. I am going on vacation for a week and hoping this does the trick so I have A/C on my trip during a heat wave. Local shop that specializes in A/C is booked for 2 weeks.

When I bought my 2002 Bird in 2015, I had a problem with intermittent cooling. In my case, the A/C worked fine when traveling at speeds greater than 40 mph. Below that speed the cooling dropped off in proportion to the engine and car's speed. At idle it blew hot air.

A little research into the symptoms lead me to replace the compressor's internal bypass valve. A quick test is to drive the car in 1st gear and bring the revs up to 4000 or so. If the A/C starts cooling, the valve could be sticking. While I'm not an A/C expert, I do have my own gauges, vacuum pump and other tools required to replace the valve. I had put car on jack stands and changed the valve with the compressor on the car. It's a little fiddly to get to but not too hard. After the valve change and recharge, the A/C air temp was 30F at idle. The A/C has worked flawlessly to this day.

Before I did the job, I contacted Ford to see if they would replace just the valve. Ford said they would only replace the compressor, evaporator and other parts to the tune of $1400. That's the only way they could guarantee and warranty the repair.

Here's a troubleshooting and valve replacement video from FordTechMakuloco. The valve part number is included in the video's description.

Good luck.

 

[NickTbird]

Update: Picked up the new low pressure switch yesterday but the A/C was working all day, so I was worried I wouldn't get to install it and know immediately if it fixed the issue. On my way home from work it stopped working so I installed the new switch when I got home and it did not fix the issue. The only thing that was different on my drive home was the humidity picked up, which does correlate to other times it stopped working, however not every time.

I called the local A/C expert and he thinks it could be the gap on the A/C clutch as he said he has experience with Ford A/C clutches having this issue and the humidity could be playing a factor in it. He told me to try lightly tapping the clutch to see if it would kick it on, but I can't get in there to do it so I am bringing it to him tomorrow to take a look and hopefully fix it. I have read others have good success with removing and cleaning the clutch with other Ford's. This is the only thing he can try before my vacation as they are booked solid for two weeks and this would be a quick job.

 

[312]

Update: Picked up the new low pressure switch yesterday but the A/C was working all day, so I was worried I wouldn't get to install it and know immediately if it fixed the issue. On my way home from work it stopped working so I installed the new switch when I got home and it did not fix the issue. The only thing that was different on my drive home was the humidity picked up, which does correlate to other times it stopped working, however not every time.

I called the local A/C expert and he thinks it could be the gap on the A/C clutch as he said he has experience with Ford A/C clutches having this issue and the humidity could be playing a factor in it. He told me to try lightly tapping the clutch to see if it would kick it on, but I can't get in there to do it so I am bringing it to him tomorrow to take a look and hopefully fix it. I have read others have good success with removing and cleaning the clutch with other Ford's. This is the only thing he can try before my vacation as they are booked solid for two weeks and this would be a quick job.

Too bad the lp switch was not it. A set of gauges would have diagnosed it if it's the clutch because you would not see a drop in pressure on the low side or a rise in the high side. Gauges are a good investment, if you learn how to use them. Your a/c compressor is located under the engine on the driver's side. You can access it by removing some plastic panels in the wheel well. You can replace the clutch alone without changing the compressor. Did you check the relay for the clutch ? You can substitute a relay from some circuit the car is not actively using , as long as it's the same relay and see if the clutch engages properly. A relay which carries high current to the clutch pack like this one may have burned contacts and only work intermittently or drop too much voltage to enable the clutch pack to work.. Relay' are cheap to replace. I have pictures somewhere of the panels to remove if you need them.PS don't overlook corrosion on the contacts of the clutch connector. Randy

 

[The Flash]

without using gauges to check the A/C pressure you are pissing away time and money.

 

[NickTbird]

Too bad the lp switch was not it. A set of gauges would have diagnosed it if it's the clutch because you would not see a drop in pressure on the low side or a rise in the high side. Gauges are a good investment, if you learn how to use them. Your a/c compressor is located under the engine on the driver's side. You can access it by removing some plastic panels in the wheel well. You can replace the clutch alone without changing the compressor. Did you check the relay for the clutch ? You can substitute a relay from some circuit the car is not actively using , as long as it's the same relay and see if the clutch engages properly. A relay which carries high current to the clutch pack like this one may have burned contacts and only work intermittently or drop too much voltage to enable the clutch pack to work.. Relay' are cheap to replace. I have pictures somewhere of the panels to remove if you need them.PS don't overlook corrosion on the contacts of the clutch connector. Randy

I believe the mechanic will be taking the clutch apart tomorrow to give it a good look over. Unfortunately I can't replace the clutch myself at this time.

I tried to remove the relay the other day to check the bottom side and re-seat it but I always struggle to get them out and didn't have proper tools at the time. I will pick one up just in case the shop thinks they fixed it but it begins to act up again, I will swap the relay to rule it out. I will start it up when I get home tonight and try swapping the relay first, but chances are it will be working and won't tell me anything.

If it still isn’t working, I will bring it to the A/C mechanic after my vacation and let them figure it out.

Thanks for the help.

 

[NickTbird]

Update: Just picked the car up from the shop. He took one look at the clutch and said it wasn't what he thought it was and he has never had to adjust this type, so he said he is certain there is nothing wrong with the clutch. They properly evacuated the system and found it to be 10oz low; clearly my mechanic didn't know what he was doing and I will never trust them for any A/C work again. Now that it is at the proper charge we will know if there is actually something wrong. By replacing the switch and swapping the clutch relay, we have ruled out both of those if the problem persists.

On my drive home from the shop the A/C seemed to be shutting off early periodically; I stopped to watch what the clutch was doing and it was staying engaged longer than before, but still not very long. It is fairly cold today though, I will know better during my drive tomorrow with warmer temperatures. I will update this thread after my drive tomorrow, if it works well during my entire drive, I will consider it fixed.

Lesson learned, don't trust anyone other than an A/C expert, even if you trust your regular mechanic for everything else, which I do (except transmission work, also will only deal with shops that specialize in them). Only reason I bought that part was because I trusted my mechanic when he said the refrigerant was good. Luckily my regular mechanic didn't charge me for a couple of my visits to their shop.

 

[312]

Update: Just picked the car up from the shop. He took one look at the clutch and said it wasn't what he thought it was and he has never had to adjust this type, so he said he is certain there is nothing wrong with the clutch. They properly evacuated the system and found it to be 10oz low; clearly my mechanic didn't know what he was doing and I will never trust them for any A/C work again. Now that it is at the proper charge we will know if there is actually something wrong. By replacing the switch and swapping the clutch relay, we have ruled out both of those if the problem persists.

On my drive home from the shop the A/C seemed to be shutting off early periodically; I stopped to watch what the clutch was doing and it was staying engaged longer than before, but still not very long. It is fairly cold today though, I will know better during my drive tomorrow with warmer temperatures. I will update this thread after my drive tomorrow, if it works well during my entire drive tomorrow, I will consider it fixed.

Lesson learned, don't trust anyone other than an A/C expert, even if you trust your regular mechanic for everything else, which I do (except transmission work, also will only deal with shops that specialize in them). Only reason I bought that part was because I trusted my mechanic when he said the refrigerant was good. Luckily my regular mechanic didn't charge me for a couple of my visits to their shop.

I will look in my shop manual to find out what type of expansion valve you use(electronic or mechanical). This is sounding more and more like a sticking TXV. Compressor is cycling on the low pressure switch which means (ruling out a bad switch) that the compressor is pulling more of a vacuum on the low side from the evaporator then it's being fed with refrigerant vapor. Blocked metering device is very likely under those conditions. By the way , i am a retired HVAC/ELECTRONIC'S instructor with a Universal refrigerant license and a MVAC license as well. Troubleshooting from a distance without reliable data is difficult at best , if not impossible .You really need to understand the refrigerant cycle and the physics of the refrigerant. Gauges are a must in your case. I am willing to bet that your low pressure switch is simply reacting to a starved evaporator coil. In other words , the refrigerant is being obstructed getting to the evaporator in your dash. Gauges would prove this right away. You would see them rapidly drop below the set point of the low pressure switch. If the system was low , you would have the problem consistently , getting worse as it got hotter outside. If it's an electronic TXV the control for it could be bad .

I have the same issues as you have. Replaced the 5 port DCCV, and no help. Had a shop evacuate system, and reservice, weeks later returned to shop and was told freon was low. Added freon, and was good for another week or so. After reading forum, it seems the O rings go bad and bypass freon, so the compressor has to be replaced. Mine was replaced about 8 years ago, and I guess is due again. Read the blogs, it seems to be a common problem (one of many) with these cars.

Freon is the old trade name for R22 refrigerant. It is not used in vehicles but in home a/c systems in the past. It seems like the name stuck to all refrigerants though. R134A is what is in our T birds. Before that vehicles use R12 .

 

[The Flash]

If the repair shop really knows the A/C system they can tell how efficient it is by comparing the Ambient temp to the system pressures and when the A/C control cycles the A/C compressor compared to the dash A/C vent temps.

 

[NickTbird]

So I still have an issue. When it is acting up and the clutch isn’t staying engaged for long, it does sometimes get cold to ice cold, likely due to it performing better with the proper charge, but the temperature is inconsistent and sometimes stayed warm. It was a beautiful day so I had the top down and only turned it on periodically to test it and sometimes I pulled over to see what the clutch was doing. I’m going to let the shop diagnose it from here and I will try to bring it to them when it is acting up. I will update this thread again when I get to the bottom of the issue.

Thanks again for the help.