2001 ford station wagon AC problem

low side gage on. Engine off, about 100 PSI. Start engine, run the AC. Low side drops to 20, then up to 40, and back to 20. Then after doing this several times, it goes back up to 100 and stays.

Low freon level????

low side gage on. Engine off, about 100 PSI. Start engine, run the AC. Low side drops to 20, then up to 40, and back to 20. Then after doing this several times, it goes back up to 100 and stays.

The only ACCURATE way to know is to draw the system down and add the specified amount of refrigerant. It sure sounds like the unit is low on freon.

low side gage on. Engine off, about 100 PSI. Start engine, run the AC. Low side drops to 20, then up to 40, and back to 20. Then after doing this several times, it goes back up to 100 and stays.

ditto

GW

low side gage on. Engine off, about 100 PSI. Start engine, run the AC. Low side drops to 20, then up to 40, and back to 20. Then after doing this several times, it goes back up to 100 and stays.

I agree with Clare. It sounds like the low pressure cut-off switch is kicking in and disengaging the A/C clutch. Then when the low side pressure rises, the clutch kicks in again. I'd also be interested in seeing what the high pressure side is showing during this time. Get a can of R-134a with leak detector dye and a UV light. Your local auto parts store should have both. Begin SLOWLY adding the 134a into the system and see if that fixes the problem. And whatever you do, do NOT flip the can upside down or else you'll be dumping liquid into the low side. If it does fix the problem, run the system at night and use the UV light to look for any escaped leak detector dye. Pay special attention to all connections and the compressor, but don't overlook the entire condenser coil and the service ports. I'll bet you have a small leak somewhere.

Low freon level????

The only ACCURATE way to know is to draw the system down and add the specified amount of refrigerant. It sure sounds like the unit is low on freon.

I agree with Clare. It sounds like the low pressure cut-off switch is kicking in and disengaging the A/C clutch. Then when the low side pressure rises, the clutch kicks in again.

CY: That's what I described. Now, please tell me why the compressor stopped working at all, and the pressure went up to 100 and stayed?

I'd also be interested in seeing what the high pressure side is showing during this time.

CY: I didn't tap into the high side, hate to lose that blast of refrigerant when I unhook my gage.

Get a can of R-134a with leak detector dye and a UV light. Your local auto parts store should have both. Begin SLOWLY adding the 134a into the system and see if that fixes the problem.

CY: That's a thought.

And whatever you do, do NOT flip the can upside down or else you'll be dumping liquid into the low side.

CY: If you add with the can upright, the UV dye stays within the can. Have to invert, to get the dye to go in.

If it does fix the problem, run the system at night and use the UV light to look for any escaped leak detector dye. Pay special attention to all connections and the compressor, but don't overlook the entire condenser coil and the service ports. I'll bet you have a small leak somewhere.

CY: And, so why did the compressor stop working at the end, and totally stop after the low side came up to 100 PSI, which should have satisfied the low pressure cutout?

I think it was low, as the compressor cycled on the low pressure cutout, a couple times. But why the compressor finally stopped working at all?

ditto

GW

low side gage on. Engine off, about 100 PSI. Start engine, run the AC. Low side drops to 20, then up to 40, and back to 20. Then after doing this several times, it goes back up to 100 and stays.

Being a Ford, he may as well just evacuate the system and replace every "O" ring, then draw it down again and charge with the specified amount of refrigerant. (0+% chance he has a few bad "O" rings - but adding die first and running it may also find a perforated receiver or some other odd leak. "O"rings on Fords are the major problem.

couple times. But why the compressor finally stopped working at all?

The computer cut it out to protect the clutch and compressor.

working at all, and the pressure went up to 100 and stayed?

when I unhook my gage.

invert, to get the dye to go in.

after the low side came up to 100 PSI, which should have satisfied the low pressure cutout?

If you draw the system down, and add the refrigerant through the low side without the system running, you can do it inverted and get all of the oil and die into the system. Then let is sit for 10 minutes or so before running the compressor.

working at all, and the pressure went up to 100 and stayed?

Clare already answered that. Can you go back out to the car and repeat what you first posted? If so, that's de facto proof that the computer shut it down to prevent damage.

when I unhook my gage.

Please tell me you are using the newer hoses that don't vent their contents when you disconnect them.

invert, to get the dye to go in.

No, it doesn't. I've found many leaks using the method I described. And if you invert a can with the system running, I cannot think of a better way to damage the valves in the compressor. Do so at your own risk. You've been warned.

after the low side came up to 100 PSI, which should have satisfied the low pressure cutout?

See above, and when the compressor shut down, the system stabilized. If you had hooked up the gauge to the high side while the compressor was off, you would have probably noticed the high side pressure was at or near 100, too. It's the difference in pressures between the high and low side that causes the system to work. You probably didn't give the computer time to reset so the clutch would engage again.

I do not mean to offend, but if you cannot grasp the concepts we've laid out here, take it to a professional because you have no business working on a closed A/C system.

low side gage on. Engine off, about 100 PSI. Start engine, run the AC. Low side drops to 20, then up to 40, and back to 20. Then after doing this several times, it goes back up to 100 and stays.

Considering his recent posts, I have serious doubts that he has the equipment or expertise required to do this correctly. He would be better off leaving it to a professional.

because the switch is failing. Those wear out all the time. GW

Those switches that I've seen normally cycle between 28psi off to 42 psi on. If you were seeing 20 psi it's probably low on freon like everyone said and also a good chance, like others have said, that the computer saw the short cycles and shut it down. If it was me and I didn't want to spend a lot of time messing with it I'd just put a can of freon in it and see how it does. Just watch the pressures as you put it in. Assuming you can get to it to feel it, I usually check the "out" pipe from the evaporator to see if it's cool or cold. If there's not enough freon it won't be cold. I'd be willing to bet that adding a can gets it working satisfactorily.

couple times on low CUTOUT. But, why did the COMPRESSOR finally stop WORKING at ALL?

On Thu, 30 May 2013 10:47:34 -1000, Geoff Welsh wrote:

Personally, i doubt there is any problem with the switch - and if it has shut down on the safety (from cycling it too often) I believe there is a reset procedure. Not sure on Ford, but on Navistar Trucks, to reset the A/C you use the cruise control buttons on the steering wheel.

With the truck not running, the key in the ON position, transmission in park, parking brake set, and left turn signal on. Using the cruise control buttons, at the same time push the left button up and the right one down to pull the codes on the dash. To RESET all codes and start the A/C again push both cruise control buttons UP.

This should reset the A/C if the check A/C light is on.

Like I said, not sure about Ford - and it will likely differ from year to year and model to model . On a '99 Crown Vic with automatic temperature control, the following procedure is required: Electronic Automatic Temperature Control Module Self-Test

The EATC module self-test will not detect concerns associated with data link messages like engine coolant temperature or vehicle speed signals. A NGS tester must be used to retrieve these concerns. The EATC module self-test will detect concerns in the system control functions and will display hard diagnostic trouble codes (DTCs) in addition to intermittent diagnostic trouble codes for concerns that occur during system operation. The vehicle interior temperature should be between 4°-32°C (40-90°F) when carrying out the self-test. If the temperatures are not within the specified ranges, false in-car temperature sensor DTCs will be displayed. The self-test can be initiated at any time. Normal operation of the system stops when the self-test is activated. To enter the self-test, press the OFF and FLOOR buttons simultaneously and then press the AUTOMATIC button within two seconds. The display will show a pulse tracer going around the center of the display window. The test may run as long as 30 seconds. Record all DTCs displayed. If any DTCs appear during the self-test, follow the diagnostics procedure given under ACTION for each DTC given. If a condition exists but no DTCs appear during the self-test, refer to the Symptom Chart Condition: The EATC System Is Inoperative, Intermittent or Improper Operation. To exit self-test and retain all intermittent DTCs, push the blue (cooler) button. The control will exit self-test, retain all intermittent diagnostic trouble codes and then turn OFF (display blank). To exit the self-test and clear all DTCs, press the DEFROST button. The vacuum fluorescent display window will show 888 and all function symbols for one second. Then, the EATC control assembly will turn OFF (display blank) and all DTCs will be cleared. Always exit the self-test before powering the system down (system turned OFF). Intermittent DTCs will be deleted after 80 ignition switch ON cycles after the intermittent condition occurs.

That ought to keep Stormy occupied for a while!!!

because the switch is failing. Those wear out all the time. GW

I've forwarded this to the fellow who owns the car, and will see what he replies. Thank you for the kindness, and consideration. . Christopher A. Young Learn more about Jesus

Personally, i doubt there is any problem with the switch - and if it has shut down on the safety (from cycling it too often) I believe there is a reset procedure. Not sure on Ford, but on Navistar Trucks, to reset the A/C you use the cruise control buttons on the steering wheel.

With the truck not running, the key in the ON position, transmission in park, parking brake set, and left turn signal on. Using the cruise control buttons, at the same time push the left button up and the right one down to pull the codes on the dash. To RESET all codes and start the A/C again push both cruise control buttons UP.

This should reset the A/C if the check A/C light is on.

Like I said, not sure about Ford - and it will likely differ from year to year and model to model . On a '99 Crown Vic with automatic temperature control, the following procedure is required: Electronic Automatic Temperature Control Module Self-Test

The EATC module self-test will not detect concerns associated with data link messages like engine coolant temperature or vehicle speed signals. A NGS tester must be used to retrieve these concerns. The EATC module self-test will detect concerns in the system control functions and will display hard diagnostic trouble codes (DTCs) in addition to intermittent diagnostic trouble codes for concerns that occur during system operation. The vehicle interior temperature should be between 4°-32°C (40-90°F) when carrying out the self-test. If the temperatures are not within the specified ranges, false in-car temperature sensor DTCs will be displayed. The self-test can be initiated at any time. Normal operation of the system stops when the self-test is activated. To enter the self-test, press the OFF and FLOOR buttons simultaneously and then press the AUTOMATIC button within two seconds. The display will show a pulse tracer going around the center of the display window. The test may run as long as 30 seconds. Record all DTCs displayed. If any DTCs appear during the self-test, follow the diagnostics procedure given under ACTION for each DTC given. If a condition exists but no DTCs appear during the self-test, refer to the Symptom Chart Condition: The EATC System Is Inoperative, Intermittent or Improper Operation. To exit self-test and retain all intermittent DTCs, push the blue (cooler) button. The control will exit self-test, retain all intermittent diagnostic trouble codes and then turn OFF (display blank). To exit the self-test and clear all DTCs, press the DEFROST button. The vacuum fluorescent display window will show 888 and all function symbols for one second. Then, the EATC control assembly will turn OFF (display blank) and all DTCs will be cleared. Always exit the self-test before powering the system down (system turned OFF). Intermittent DTCs will be deleted after 80 ignition switch ON cycles after the intermittent condition occurs.

That ought to keep Stormy occupied for a while!!!