: ac off light is on...cant get it to turn off



kycycles
05-01-13, 03:16 PM
the ac has been working fine...i was getting a service ac soon light, but was still blowing ice cold. now, the "ac off" light is on and i cannot turn it off. I hooked the freon up to send some through the system, and nothing happened. i did not get a manual with this car, so i am going to find the fuse blocks and check that. i also have the battery unhooked right now to try to reset the system.

any thoughts.

i have no codes on the scanner.

is there any way to test the compressor?

glake89
05-01-13, 04:27 PM
From the SM-
The A/C switch will illuminate A/C OFF when the A/C switch is selected.

You may have a 'B' DTC; get code read at a parts store and advise.

Your 'reset' may work if there is a module communication problem.

kycycles
05-01-13, 04:50 PM
From the SM-

You may have a 'B' DTC; get code read at a parts store and advise.

Your 'reset' may work if there is a module communication problem.

dang...so that probably means the compressor has crapped out. I have a scanner..i am not showing any codes.

unhooking the battery did not do anything for me. i only saw one fuse in the box that had anything to do with hvac...it was fine

glake89
05-01-13, 06:07 PM
Does your scanner do all 4 code types; P,B,C,U?

kycycles
05-02-13, 10:24 AM
Does your scanner do all 4 code types; P,B,C,U?

yes, i believe it idoes. its an obdii/eobd multilingual scanner

glake89
05-02-13, 12:00 PM
If you had a 'service AC' message, you have a code, maybe in 'history'. Try a parts store for a free read.

kycycles
05-02-13, 12:49 PM
will try that as well. the code would just pop up randomly.

n7don_srx
05-02-13, 08:13 PM
If one of the servos that control the position of doors in the ac system fails it will set a "B" code also. Generally the system will still blow cold air it just won't be directed to the correct level. I'd caution about just putting refrigerant into the system without confirming it's low.
Have you looked underhood to confirm what the compressor is doing.... running, not running?
As a comment, most consumer grade scanners only read P (Powertrain) codes. If the system has set an error it should be stored in the ECM's history (as glake pointed out) even if the CEL isn't on.

kycycles
05-02-13, 09:24 PM
i dont see or hear the compressor doing anything.

the system did not take any refrigerant at all...which i assume means it was full

also, the wife cranked the heat up this morning and the "Ac off" indicator never went away.

n7don_srx
05-03-13, 08:59 AM
the system did not take any refrigerant at all...which i assume means it was full
.

The correct way to determine if the system is charged with the right amount is to evacuate all the refrigerant and refill with the specified amount. It's fairly easy to over-charge a system and then bad things can happen. Do you have a trusted shop to evaluate your problem?

kycycles
05-07-13, 07:28 PM
ok, the ac started working again yesterday. We are now able to turn the ac indicator light on and off and its blowing cold as ice. I still have not had time to run diagnostics on it, but will soon

we did have a nice drop in temperature around here ...from the high 70's to the mid 50's if it matters

orandaberg
05-08-13, 09:01 AM
Good! Let us know so if it happens to someone else it can be fixed?

kycycles
05-08-13, 10:02 PM
today the ac was intermittent. i ran the codes and got the following

p0120
c0450
b0103
u0001

any thoughts?

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ok, so after some research...none of the trouble codes have anything to do with the ac? what do i do now? also...does anyone think that the outside temp change has anything to do with this issue? it was very muggy today and temps are getting close to 70 again. the ac was on and off for no apparent reason

orandaberg
05-09-13, 03:53 AM
The compressor going out?

glake89
05-09-13, 10:08 AM
You have shorts to voltage, to grounds or open circuits, most likely the latter as well as lost or poor ground connections. These cars are very ground dependent for the electronics to work.
Remove, clean and reattach all ground connections you can find, esp. at the ECM. (1 of the ECM bolts is a grd. plus a redundant grd. wire).
If that doesn't do it, remove, clean and reattach wire harness connectors at ECM and ECBM. Do this w/ neg. battery cable disconnected.

conedoctor
05-09-13, 06:36 PM
So once one of the boxes looses a ground and assume it gets the ground again does it take a key cycle or does the box that lost it keep looking at a set sample rate?

glake89
05-10-13, 10:03 AM
A DTC will set when a condition exists for 1 to 5 seconds, depending on what it is. If it doesn't reoccur in 2 or more drive cycles the MIL will go off but the DTC remains in history as well as freeze frame. I think once a connection begins to fail it's not likely to permanently repair itself although it may be OK for extended periods.

kycycles
05-10-13, 04:15 PM
ok guys...i will check the connections as mentioned above. But its hot am humid with rain today and the ac stopped working again. it will be cold again this weekend, but i have a feeling when the temp drops the ac will start up again

glake89
05-10-13, 05:03 PM
See if you can get the freeze frame records for the codes you found. Might lead us to a solution.

kycycles
05-12-13, 09:53 AM
i will get the freeze frame next time i go to the parts store.

like clockwork...outside temp goes down, everything works fine...temp gets around 70-80, it stops working.

glake89
05-12-13, 10:16 AM
Found this in SM-

"The A/C refrigerant pressure sensor prevents the A/C system from operating when an excessively high or low pressure condition exists.

If the ECM detects a failure in the A/C refrigerant pressure sensor or circuit, the GMLAN message sent to the HVAC control module will be invalid. The HVAC control module will then send a request to the radio for display of the SERVICE A/C SYSTEM that will be displayed on the DIC. The HVAC control module will also display A/C OFF on the module as long as the condition is present."

kycycles
05-12-13, 11:34 AM
where is that sensor?

glake89
05-12-13, 11:56 AM
You get to it by removing the front air deflector so it's down near the bottom of the radiator, but you have to discharge the system to replace it. The sensor may/may not be bad. The refrigerant charge may be just borderline so the ambient temp. would cause enough of a pressure change to trigger a fault. Go to an auto AC shop and have them check. Don't let them talk you into a discharge/recharge, just bring the system into spec.

kycycles
05-12-13, 12:07 PM
according to the gauge on the recharge bottle i bought, the system is full, but i am not sure how accurate that is.

glake89
05-12-13, 12:36 PM
Here ar the pressures you're looking for, at ambient temp. (shown)-
Above 16C (60F) 345 kPa (50 psi)

Above 24C (75F) 483 kPa (70 psi)

Above 33C (90F) 690 kPa (100 psi)

See how much the pressure changes (static pressure) with 15 deg. ambient? Sounds to me like you have too much freon in system.

edit. note you should only add freon when system is running.

kycycles
05-12-13, 12:40 PM
i thought the same about too much pressure. i am going to switch out cars with the wife and get this thing in my shop this week. i will keep you guys posted. thanks for all the info

kycycles
05-15-13, 11:01 PM
i finally got the code on the scanner p0532 pressure sensor. the parts store does not offer this. I guess the dealer is my only option??? about how much should i expect?

n7don_srx
05-16-13, 07:46 AM
i finally got the code on the scanner p0532 pressure sensor. the parts store does not offer this. I guess the dealer is my only option??? about how much should i expect?

You need to independently verify this is the correct part for you SRX. Per Amazon's fitment it's correct for my 07 (but they've been wrong before)
http://www.amazon.com/ACDelco-15-50153-Switch-Assembly/dp/B000C9C7AU/ref=sr_1_1?ie=UTF8&qid=1368704497&sr=8-1&keywords=1550153
Also as glake pointed out the system must be discharged to replace this item.

glake89
05-16-13, 10:27 AM
0532 does not necessarily mean the sensor is bad, it also means pressure is low. Have an AC shop check first!

kycycles
05-16-13, 01:35 PM
0532 does not necessarily mean the sensor is bad, it also means pressure is low. Have an AC shop check first!

its definitely not low. at least from what i can tell on my gauge. But i will keep you posted.

conedoctor
05-16-13, 01:49 PM
The guys are trying to lead you to water, take it to an AC shop.

What does the gauge read? does it have pressure or just the words full?

kycycles
05-16-13, 02:01 PM
when i first got the car i checked it with the gauge on the coolant refill bottle. i dont remember exactly what it was, but with the temperature at the time, it was where it needed to be.

i am not sure how to check it again without the compressor running.

conedoctor
05-16-13, 03:07 PM
did you check hi and low side?

glake89
05-16-13, 04:27 PM
You need a set of AC gauges or a single gauge that will read as high as the numbers I posted @25. Those are STATIC pressures (compressor not running). The throwaway gauge on the can is worth exactly the same as the empty can.

conedoctor
05-16-13, 05:36 PM
If only there were a shop or something that just worked on AC systems, oh wait........

kycycles
05-16-13, 05:51 PM
If only there were a shop or something that just worked on AC systems, oh wait........

that would be no fun. cant learn unless i do it myself right?

glake89
05-16-13, 06:06 PM
Some things are best left to others, unless you like to spend money.

kycycles
05-16-13, 06:31 PM
i have never really had any problems charging an ac system or working on one on most of the cars i have had worked on over the years. i am being a little more careful on this one because there is more involved.

however, if i get to the point were i think its too much, i will take it to the ac shop, but i am not there yet. i will go buy the gauges i need and check the high and low sides and see whats up.

conedoctor
05-16-13, 06:57 PM
Not saying you don't have the ability or able to learn but you may do more harm than good, I'm all for understanding how it all works but I don't have a problem letting trained people who have all the tools get it done right the first time.

Do you have to add oil or was it in the coolant you used, what coolant did you use and where did the original charge go?

kycycles
07-01-13, 02:30 PM
i finally got a chance to hook some gauges up. the ac started working today after driving down a gravel road. I am going to check the connection at the sensor...it sounds like it may have a short.

any way...with the compressor running, i am showing 20lbs on the low pressure side and 58 pounds on the high pressure side.

which side do i need to go off of...its low regardless(according to the numbers posted earlier in this thread)

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stupid question...nevermind about what side to go off of.

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right now, the weather channel is reporting that it is 75 outside. that being said, i am down in the valley some, so i would say its probably not that hot. If i go by the numbers below, 58 pounds should be too much freon...right???

Above 16C (60F) 345 kPa (50 psi)

Above 24C (75F) 483 kPa (70 psi)

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another question...i am only supposed to add freon when the compressor is running. what do i do since its not running?

glake89
07-01-13, 02:54 PM
Those pressures are static (not running) and sound about right. You only add when running. Reading the SM it gives 2 quantities of freon to use (they go by weight of freon), 12-15 lbs. in one discussion and 1.26 lbs. in another. When it runs, if the air is cold it's probably OK. If not, I can't imagine an AC shop would charge too much to bring it to spec. Sounds like you're on the right track looking for poor connections. Maybe the console switch itself.

Found the chart for running pressures.
121898

kycycles
07-01-13, 04:00 PM
wow 238 psi on high side??? my gauges dont go that high..they stop at 90. it turns out the pressure switch had a loose wire....that is fixed and it seems to be running like it should. however,,,its not as cool at idle....i did let 8 psi out to bring the high side down according to the chart shown on here earlier

SFVetteman
07-01-13, 06:59 PM
It looks like you have a low side gauge. A decent set of A/C gauges can usually be picked up for about $50 on ebay. They are necessary to have because a high side gauge can help indicate an overcharged condition or a bad compressor. That said, automotive A/C refrigerant pressures can vary quite a bit especially on the high side. Since you have a low side gauge, look for a low side pressure of 40 psig +/- 5 psig with the system running, of course.

Bill

kycycles
07-02-13, 09:31 AM
i am an idiot...i was looking at the line on the gauges for 134a...i was in a hurry and completely ignored that fact that the psi reading was in the center of the gauge. it works great now....i will send a pic of my gauge reading after while.

now its on to the rear wheel bearing, power steering leak, power steering assist an stability control issues..