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Discussion Starter #1
I got my AC vacuumed out and recharged. I'm having problems with the AC cutting out. Sometimes it goes from warm, to so cold you can see the air coming out of the vents. I asked the guy at the shop that did the work what might be going on, and he said it sounded like the temperature control switch wasn't working right. I cleaned the sensor, which was very dirty, but I'm still having problems. How much control does the Climate Control Panel have over what is going on? My display is shot, and it's really hard to make out what temperature it's set at, let alone what else is going on. I've recalibrated it several times by pressing the auto and off buttons at the same time. I'm still having issues. What could be the cause of this?

Also, I checked Eeuroparts website and they have one listed for my car that has knobs and buttons. Is that the replacement for the digital ones? I wouldn't mind one like that, if it made everything work like it should.
 

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You cannot just replace ACC with MCC... I would really recommend getting the ACC unit repaired to see what's going on.

That said, the point of ACC is to maintain a constant temp - what you're experiencing is not normal. Probably worth checking the cabin temp sensor to be sure it's reporting correctly, and that the fan is working properly to suck cabin air and blow it across the sensor. If that's not happening, ACC may not be able to control the temperature correctly.
 

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I will also add I ran into something similar to this twice:


1. Grotesquely overcharged AC was actually intermittently seizing the compressor. Noise and a tangible change in engine response accompanied so I doubt this is your issue.


2. Slipping clutch on a compressor resulted in intermittent functionality and alternating bursts of warm and cold air
 

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Discussion Starter #4
I will also add I ran into something similar to this twice:


1. Grotesquely overcharged AC was actually intermittently seizing the compressor. Noise and a tangible change in engine response accompanied so I doubt this is your issue.


2. Slipping clutch on a compressor resulted in intermittent functionality and alternating bursts of warm and cold air
I'm starting to wonder if it's not the compressor. I sat with it in park and listened to what was going on. The compressor will cycle normally for a few minutes. Eventually, the engine will rev up slightly and return to normal idle. At this point, the compressor is clearly not engaged. The air will begin to get warm. Then, eventually, the compressor will kick on hard and make the engine stumble. The air will get cold. It will go through the last 2 cycles a few times, and then the compressor will go back to normal cycling for a few minutes, and then repeat the cycle where the engine revs up, and the cycle where the compressor kicks on making the engine stumble. And so on, and so on.

Sent from my SM-G892U using Tapatalk
 

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At this point it could be any number of things - you will probably need to check & watch pressures. Check the expansion valve, the receiver/dryer. The whole system has to work for any of it to work. *Probably* if the compressor works at all it works.
 

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Are your radiator fans working? Both of them?
Almost sounds like the system is hitting the high pressure cut off and shutting down the compressor.

As stated prior, I would get a set of gauges and check the pressures.
 

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Discussion Starter #7
Are your radiator fans working? Both of them?
Almost sounds like the system is hitting the high pressure cut off and shutting down the compressor.

As stated prior, I would get a set of gauges and check the pressures.
I'm not certain both cooling fans are working. I honestly don't even remember how each fan operates, and when. A cooling fan almost never runs. One used to kick on and off with the compressor, and one sometimes kicks on when the engine is really hot, but no fan continues to run when I turn the car off. I always thought that was odd, but the car never overheats, so I never thought much about it.

I will get a set of gauges. I've been wanting to, but now I have a need for them, and a reason to buy a set.
 

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Discussion Starter #8
Can anyone tell me how the two cooling fans are normally supposed to operate?

Sent from my SM-G892U using Tapatalk
 

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There is only one fan (but it will run at two speeds - depending on market and equipment level).

Whether it runs at high or low speed (or not at all) depends both on the coolant temp and AC pressure, with different variances triggering a different speed. The WIS contains all the specifics, but its pretty simple to jump either the high or low speed relay and see if both fan speeds work.
 

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Discussion Starter #11
I got it all sorted out. The cooling fan resistor was bad, so the fan wasn't working on low. I corrected the problem, and now the AC works great.
 

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Discussion Starter #13
Great, thanks for the update
It worked well for a 30 minute drive home last night. I was able to make it very cold inside the car. Today however, it's 85 degrees and very humid and the system isn't working correctly. The compressor cycles on and off every 5-10 seconds, and then eventually, the compressor stop running for several minutes. Almost the same symptoms as before. Time to get that set of manifold gauges.

Can anyone tell me how to repair the ACC control? Is that something I can do, or does it need to be sent away or replaced? There's a U-Pull-it place about 3 hours away. I'm making plans to go grab a bunch of parts. Perhaps I can grab one that still works. They're not very expensive at the U-Pull-It yard, but there's no way to know if they work without plugging it into a running Saab (or is there?).

Sent from my SM-G892U using Tapatalk
 

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Is this the same issue to why you had the system vac’d and recharged?

The cooling fan is still working the way it should?


A set of gauges will tell the story if the compressor is cutting off due to high pressure.
 

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The ACC panel's display is pretty difficult to repair, compared to the SID, from what I've heard. It's probably best to get a used one. Luckily the ACC displays don't go bad as often as the SID ones do, so you have a better shot of getting a good one. It would probably cost you $100 to get your existing one repaired, assuming it's just a screen issue. if there are more issues, then replacement is really your only option.
 

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Anti-frost thermostat sensor may stop AC compressor...

If the larger of two AC pipes at expansion valve on engine side of firewall is ice cold, then anti-frost thermostat attached to same pipe on evaporator inside cabin may be cutting power to compressor clutch via relay. I noticed compressor cycling when getting little or no airflow due to a failing cabin fan blower motor control module, which only ran on low speed or not at all.
 

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Discussion Starter #18
I found the best way to fix the ACC screen is just to buy a replacement screen with cable and a ZIF connector that connects it to the PCB, solder on the connector and you will never have a issue with it again.
Are there any sources for these items that you could recommend? Does PCB stand for Printed Circuit Board?
 

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Discussion Starter #19
Is this the same issue to why you had the system vac’d and recharged?

The cooling fan is still working the way it should?


A set of gauges will tell the story if the compressor is cutting off due to high pressure.
I removed the compressor to give me more room to make a repair that wasn't AC related. In retrospect, I could have just worked around the compressor. The issue I am having now existed before the "vac'd and recharged". I bought the car last year, and had the system charged at a local shop last August. I've been having this issue from the get go.

I bypassed the resistor for the cooling fan, so no, the cooling fan is not working as it should, but it does run when it's supposed to. It just runs on high when it runs. That doesn't necessarily seem like a bad thing to me.

I'll have a set of manifold gauges next week to better see what's really going on.

I'm starting to suspect that the compressor clutch is sometimes slipping. I've started to notice that when the system stops cooling, the engine RPMs go up to about 2500. The AC system seems to be still engaged at this point. If I set the ACC to off, the engine drops back to a normal idle of about 1800 RPMs. If I don't intervene, the engine RPMs will stay at 2500 for 30 second - 1 minute and then inevitably the system will eventually turn the compressor off for a minute or two.
 
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