On vacation and AC keeps shutting down.

[brmurph]

I am driving to Minnestota from Texas and the AC keeps giving the message "low refrigerant AC off" and throws the B1347 code (which is very low refrigerant). Luckly I know how to reset the code (thanks to this board), it will then run just fine (very cold) for sometimes 30 minutes, other times it will run all day.

I stopped at a cadillac dealership for them to look at it and they said the AC was .5 lbs low and evacuated the system adding a total of 2 lbs (I think). Within a few hours of driving I have the same problem happen all over again. From what I have read in the archives the problem must be low refrigerant, plugged orfice tube or faulty low pressure switch. So through process of elimination I thought I would try the low pressure switch next. I don't have my manuals with me so anyone know where this one is located? Also can I replace this without any refrigerant leaking out or does it need to be evacuated again?

I did get B1315 (Evaporator Inlet temp sensor short circuit) one time but only saw that in the history never current.

Thanks.

[Ranger]

I am not sure if it can be replaced without evacuating the system. I would guess not, but Kevin most likely knows for sure. It is located on the passenger side line, between the accumulator & the firewall as I recall. At least that is where it was on my '97.

[Bruce Nunnally]

If it is leaking, which seems most likely, when you get a recharge at the next stop, ask them to add some dye so you try to determine where the leak is? Then if the NEXT place can't repair permanently, you can patch it enough to hold charge til after your trip?

[BodybyFisher]

Here is the low pressure switch location, the low side pressure switch is #13. As Ranger said, the switch can not be replaced without evacuating the system, I needed to replace mine. IF and ONLY IF you determine that you have adequate freon charge, and in fact the switch is bad, you can JUMP the switch, BUT ONLY ONLY if you have an adequate freon charge, and you are confident its the switch. I jumped mine when it was bad. Obviously you could have the system evacautated and replace the switch it was about $25 from caddy...look at the orifice tube while its evacuated also... to see whats happening, but if the pressures were wrong the caddy dealer would have picked that up.. Good Luch

[brmurph]

Thanks guys this is what I needed to know. Will stop at the next dealer and have them replace the low pressure switch and have them check the orifice (should have done that the first time :-). They did add the dye and could not find any leaks so I think I am good there. Since this is an intermitent problem I don't think it would help to jump the switch as I can clear the codes while driving and the compressor starts working again (for the rest of the day), would it?

Thanks again.

[caddypete]

Not always that switch I have jumped all my switches and still can't get mine to stop the code, I can't even get the code to clear.Let alone get my air to work.It has been in the shop twice so far, the first time they evacuated the system.,cleaned it and filled it, the code remained, they cleared it with a tech2, it still came on, no air, they jumped the compressor bypassing the computer, air ran fine.They disconnected the battery for 1/2 hr to clear computer,as soon as they started the car the low refrig, air turned off display came up, end of that day, no charge for work told to bring it back another day, dropped it off in the afternoon a few days later, they bypassed different sensors, the codes kept switching to a different code still comp locked off,end of day.They think it may be a bad sensor that shuts down the comp,Since they checked all sensors on the air system including the connections at the climate control under the glove box.The only thing left to check before they give up is the "ac off"button on the climate control panel and the low pressure cut out sensor under the drivers kick panel. (it has a dark green wire to it, in case you need to know, I have the wiring diagram they left in my car ). At this point I would rather the car just didn't have safety sensors and the compressor burned up it would be a lot less aggravating,seeing I already purchased a remanufactured compressor and have no use for it because they know there is nothing wrong with the air except the computer locked it off.The only good thing about it all is the shop has not charged me a dime yet saying "can't charge you for something we have not fixed yet" I hope yours is a much easier problem to fix

[brmurph]

I did what BBF suggested and jumped the low pressure sensor using a paper clip, its been 2000 miles without the code or message and the AC is blowing colder then it ever has (down to 42 degrees at the vents with 95 degree temp outside). So does this mean it is most likely time to replace the sensor or is this just the symptom and something else is the problem?

Any thoughts?

[navion]

Just a caution. If you are SURE that there is and adequate charge of freon and oil, then you will be OK.

BUT, if the freon charge or the oil is low, you stand the chance of burning up the compressor.

I would take it in and have the l/p switch replaced. When they evacuate the system, they can tell how much freon is actually there. If it is low, then you have a leak somewhere. The Evaporator could be leaking and you may not see the dye there.

Take Care,

Britt

[BodybyFisher]

As Britt mentioned, if you have been to an AC shop and the system is charged to spec, its either a bad connection (at the sensor) or a bad sensor. My sensor was acting up also but differently, it set the code immediately and I believe it was damaged from the system being discharged for over a year. Yours sounds intermittantly bad... Its cheap enough, and by jumping it, you have tested the wiring as being ok..

This sensor senses pressure in the AC system and closes contacts (that is why when you jumped the wires it was as if the sensor closed the contacts). Why its dangerous is that IF you system IS in fact low in refrigerant you can damage your compressor, if you have physically jumped the switch.

[KHE]

You really need to recover and weigh the charge - if it is low, you have a leak. If it is 2.0 lbs., then I would suspect the sensor. Usually, when the system says it is low on refrigerant, it IS low on refrigerant.

[brmurph]

You really need to recover and weigh the charge - if it is low, you have a leak. If it is 2.0 lbs., then I would suspect the sensor. Usually, when the system says it is low on refrigerant, it IS low on refrigerant.

Would it be low on refrigerant even though the system is cooling better then it ever has? I am measuring 42 degrees at the vent with almost 100 degree ambiant and the best I have had in the past is 48 (I have had this car since 35000 miles and it now has over 110000).

Thanks.

[Ranger]

If it is cooling that well, I would guess that it is not low.

[BodybyFisher]

You really need to recover and weigh the charge - if it is low, you have a leak. If it is 2.0 lbs., then I would suspect the sensor. Usually, when the system says it is low on refrigerant, it IS low on refrigerant.

Would it be low on refrigerant even though the system is cooling better then it ever has? I am measuring 42 degrees at the vent with almost 100 degree ambiant and the best I have had in the past is 48 (I have had this car since 35000 miles and it now has over 110000).

Thanks.

That is incredible cooling at 100 degrees outside temp, incredible, I think that is better than it was designed for, Kevin?, a 58 drop, wow. Kevin and I are very much the same, that is why I have been cautious in telling you to jump the sensor along with having a shop check to see if its really low or not. However as Ranger said, you are getting incredible performance. Since I wear a belt and suspenders however, when you have your system evacuated to change the cheap sensor, I would have them weight the coolant for safety sake.