# A/C problem



## obermd (Mar 3, 2012)

Have the dealership actually test the difference between the high and low pressure systems on the A/C coolant.


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## Tomko (Jun 1, 2013)

I wonder if there’s an intermittent on the ambient air temepersture sensor? 

If the BCM looses contact with this sensor it will command the compressor to shut down as a fail safe protection mechanism.


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## jblackburn (Apr 14, 2012)

Sounds like an AC clutch issue...but the Cruze doesn't disengage + reengage the clutch like older cars, so it shouldn't be worn much.

I'd ask that they check out the cooling fan (this is known to fail on Gen 1 Cruzes) and possibly temp/pressure sensors as well. Ask them to take the car for an extended test drive rather than a quick spin around the block and hopefully it'll act up for them as well. It's frustrating to troubleshoot an intermittent issue.


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## obermd (Mar 3, 2012)

Tomko said:


> I wonder if there’s an intermittent on the ambient air temepersture sensor?
> 
> If the BCM looses contact with this sensor it will command the compressor to shut down as a fail safe protection mechanism.


It will also shutdown the compressor if the high side and low side are reporting too far apart. In either case the only way to properly diagnose this is to test directly and not trust the BCM.


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## Robby (Mar 1, 2013)

You may be confusing the dealer.........you did confuse me.

So.....'A/C Stops' means what???? Cabin fan stops running OR fan is blowing hot air?

Why the question? Well, I've run across blower motors that randomly shut off.......could be interpreted as 'A/C Stops blowing cold'.

Rob


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## Grazitp (Oct 25, 2014)

Ok, cabin fan continues to run, blowing warm air.


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## Robby (Mar 1, 2013)

OK.....being in Spring Grove we are enduring the same weather.

Few are aware but the Cruze A/C design will automatically be in recirculate without the light on the button IF the temperature control is at maximum (counterclockwise) rotation.
Although the pressures are (maybe) correct there is a chance you are experiencing 'freeze over'.

The evaporator core will freeze the condensation across most of the core, forcing the fan blown air around it and through every crack it can find.
This, of course, results in poor cooling.
When you shut the car off, the evap. core defrosts somewhat and you have cool air till it re-freezes.
This would be why it cools well at the start of the drive (evap. at ambient and dry), and then after thawing a bit only takes a few minutes to refreeze over.

So, the way to not have the A/C in unwanted recirculate is: A/C on at max cooling.....press the recirculate button once and you will see the light go on, and then press again so the light goes off.
This is how you force the system, when in max cooling, to pull outside air and reduce the chance of a freeze up.

Try it and if the problem goes away it is a indicator of a very slight undercharge (134 behaves weird......over charge= poor cooling, slight undercharge=freeze prone, a bit more undercharge=lousy cooling, same as overcharge. )Your call if want to address it.

This is why using the gauges as though you are servicing R-12 is a bit of a crapshoot.
IMO, the only way to get these new high performance A/C systems dialed in is to use a formal evacuate and charge by weight machine.

The other thing you need to check is to determine if the compressor is engaged while the 'not cooling' event is taking place.
If you find the compressor clutch not energized shut the car off for the 15/20 minute period you describe. Re-start and recheck.....if the clutch is now energized you likely have a sticking low pressure switch.......they will stick 'open' when hot and recover as they cool down.

THAT component failure will make a mechanic nutz......it has me, more than once.....maybe 3 times in over 50 years but it still happens (mechanical pressure switch......changeable with no loss of refrigerant FYI).

Good Luck!

Rob


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## snowwy66 (Nov 5, 2017)

OP describes the classic sympton of expansion valve. 

High pressure too high, Low pressure to low. Shuts the compressor down till low builds back up. Repeat cycle. 

My semi had the exact same sympton as OP 3 weeks ago. 

Wonder if the dealer actually checked the pressures or just checked for freon.


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## revjpeterson (Oct 2, 2013)

Quick/Simple/Cheap option to try: Swap the A/C clutch relay (I think it's #1) with another compatible relay from the under-hood fuse box (I think 4 and 5 control windshield wiper functions). See if the A/C problem resolves, and see if you develop a windshield wiper problem instead. If so, it was the relay. If not, at least it didn't cost you anything but 90 seconds of your time, and you ruled out the relay.


Too many times I've searched and tested and even replaced parts, just to find out I had a fuse/relay problem that could have been easily corrected. So, now, I always start by verifying all related fuses and relays are ok before going farther.


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