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  1. #1
    Join Date
    Aug 2010
    Location
    Ajax, Ontario, Canada
    Posts
    65

    Post Any auto mechanic in the house?

    First of all, i don't know where to post this so mods, pls move this to wherever it belongs.

    I brought our family gmc acadia to the local dealer for a leaky tire valve, wheel balancing & alignment service. In short, it had nothing to do with the engine bay area. Everything was done and paid for. The next day the a/c stopped working. Brought it back to the dealer today, 5 days later due to work, and was told it's low on charge. We've never experienced any problem with our a/c throughout this record breaking summer. Besides, there are always tell tale signs of a leaking system. Told the service manager all the facts he just shrugged it off with "the work we did had nothing to do with your current a/c problem". Is this a coincident or what?

    Here's the fact i gathered: When a/c button is pressed, it flashes 2 times and stays off. Ambient temp sensor is working fine. The closest I googled is a 3 flash = low on charge. I know something is preventing the a/c clutch engaging.

    Anyway, I am planning to tackle the problem with coming long weekend. Any hints are really really appreciated.

  2. #2
    Join Date
    Apr 2012
    Location
    winnipeg
    Posts
    1,330
    you need to trust your dealer..... or find a new one....
    it was working.... played with it.... now its broke.... whats the going hourly rate for HVAC repair

  3. #3
    Join Date
    May 2012
    Location
    Upper Michigan
    Posts
    3,589
    Sorry no DIY advise here lol.

  4. #4
    Join Date
    Sep 2007
    Posts
    176
    what yr, how many miles?
    car ac compr. will seldom last more than 100K then the shaft seal gives out, and the low pressure sw stops the compr from coming on

  5. #5
    Join Date
    Feb 2010
    Location
    Calgary, Alberta
    Posts
    1,157
    Gmc Acadia? Not under warranty anymore?? Those aren't that old...
    Ask them to put some dye in and find the leak. You can always take it somewhere else to get the repair.
    Low pressure switch could be shorted as well.
    You could also go to your local HVAC supplier like WWG and get the access fitting adapter for your gauges to fit on the suction side of your car.
    Being a 313a, you should be able to figure out what's going on.

  6. #6
    Join Date
    May 2006
    Location
    Ft. Worth, TX
    Posts
    2,201
    If you are low on freon, the compressor will not kick in. Here's an Acadia forum where they are discussing all the reasons they have a freon leak:

    http://www.acadiaforum.net/index.php?topic=9614.0

  7. #7
    Join Date
    Aug 2010
    Posts
    3,729
    Quote Originally Posted by dukebbb View Post
    "the work we did had nothing to do with your current a/c problem". Is this a coincident or what?
    Ask a Chevy forum. This is very much vehicle dependent. If any of A/Cs electrical or refrigerant pipe routing is within the potential impact area from points of access for the alignment process it can be related. You have to ask someone who's familiar with that car.

    EPA 609 and 608 certification trainings aren't interchangeable because HVAC-R and MVAC are sufficiently different and have little in common besides theory of operation.

    Contrary to what you were told, MVAC fittings are not used for HVAC-R.
    R134a uses quick fittings that are only used for MVAC. If the compressor won't engage AT ALL because of charge level, it has to be low enough that there's no liquid refrigerant left at all. You know this is the case when you connect a gauge to one of the ports and the static pressure is below what it should be based on R134a PT chart. For all intents and purposes, if it falls below saturation pressure, its considered total loss of charge. If it was working before you took it in and now there's a total loss of charge, I would certain suspect their wrong doing.

    The only way to know the charge level is by recovering the charge and comparing whats recovered against factory specs. Some cars use fixed displacement, others use variable displacement so pressure readings are only guidelines.

    First thing I would probably do is look for A/C lines near the alignment access and look for any signs of physical contact (fresh metal, dents, tool marks, etc)

    On some cars the low side port is only used for diagnosis and can require removal of body parts to gain access. On those cars, refrigerant is weighed in with a heated charging cylinder or automated A/C service equipment via high port. Usually charge level is critical to 1/4 to 1/2 oz on newer cars.

    Here's the fact i gathered: When a/c button is pressed, it flashes 2 times and stays off. Ambient temp sensor is working fine. The closest I googled is a 3 flash = low on charge. I know something is preventing the a/c clutch engaging.

    Anyway, I am planning to tackle the problem with coming long weekend. Any hints are really really appreciated.
    Ask Chevy forums. They'll know about these specific codes.

    Auto techs shouldn't DIY their shop's HVAC system and vice versa.
    Getting to components and removing interior parts without damaging them are the most challenging parts of automotive repair. I'm sure dealers do damage a whole bunch of trim pieces in process and they're well stocked on the ones they damage often.

    There are safety & loss prevention considerations unique to auto A/C such as avoiding accidental SRS deployment during service, which is a costly mistake.

  8. #8
    Join Date
    May 2006
    Location
    Ft. Worth, TX
    Posts
    2,201
    Is the fan motor set on 1, 2, or 3?

    http://www.chevyavalanchefanclub.com...;topic=84986.0

  9. #9
    Join Date
    Aug 2012
    Location
    Upstate, SC
    Posts
    38
    IMHO if you blow the air bag just by connecting your manafold, Then you shouldn't own a manafold, or even check your oil! Yes they can go off if you are messing with the sensors or the bags themselves, but not as easy as some would have you believe. Check your owners manual on how to disable the airbags to be sure, but for most vehicles you disconnect both battery cables, leave at least one door open and wait about half an hour or so. But remember, as soon as you reconnect the battery cables, the system will be armed again. And I've never come across a system that you couldn't just add a little through the suction port, but I've also never seen a million dollars, and we all know that exists! good luck!

    P.S. I am EPA certified in sections 608 and 609!

  10. #10
    Join Date
    Aug 2010
    Location
    Ajax, Ontario, Canada
    Posts
    65
    Ok

    I did a quicky pressure test before heading to work n it seems my total charge was exhausted. This is the last thing in my mind since it happened over night n there was no issue watsoever before.


    Sent from my Nexus S using Tapatalk 2

  11. #11
    Join Date
    Aug 2012
    Location
    Upstate, SC
    Posts
    38
    Get the dealer to fix it at no charge if you can, but if not just charge it yourself. I feel sure you can charge an air conditioner, or you wouldn't be here. Just charge it as you would any system. good luck!

    P.S. Find and fix the leak first!

  12. #12
    Join Date
    Aug 2010
    Location
    Ajax, Ontario, Canada
    Posts
    65
    I actually felt closure, at least now i know where to look. I'll do leak checking later and hopefully the charge was vented. Otherwise its gotta be smth big.

    Yeah i've weighed in a few autos including 2 of our shops vans. Kinda looking foward to this wkend.

    Thanks guys


    Sent from my Nexus S using Tapatalk 2

  13. #13
    Join Date
    Aug 2010
    Posts
    3,729
    Quote Originally Posted by RLBisTCB View Post
    IMHO if you blow the air bag just by connecting your manafold, Then you shouldn't own a manafold, or even check your oil!
    I get the impression that he's going to DIY repair this.

    If it involves getting to the evaporator, on some cars that means taking off the steering wheel and basically taking out the whole dash to get to the core.

    Gaining access to condenser can involve dropping the bumper.

    This is why I included SRS warning.

    And I've never come across a system that you couldn't just add a little through the suction port, but I've also never seen a million dollars, and we all know that exists! good luck!
    Here's an example. Very common car. I didn't say you can not add provided you want to do all that. Consider the labor time this procedure would add without having the equipment to charge via the high port.

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