Jump to content

Recommended Posts

Posted

Yes, get a set of a.c. Guages (not the cheap low side can adapter). Connect with system off. Hi and Lowell should match in the 50-100 range (depends on air temp). System on, lo 30-40 and hi 200-300.

Posted

Thank you for the reply.  I think you are right, I"ll plug the pressure switch back in and start over again,  however I am not sure if my scanner can provide the info needed and I'm not sure I am a good enough scanner user to get the info I need .   Also I am leaving for a ski trip to Montana next week and wont get back to that truck until the week after that.   I will revisit this site and report what I learn after I get a chance to work on the truck again, but probably won;t be until close to the end of the month. I very much want to thank you for your ongoing help, you have steered me in a different direction. I will report what I learn.                       Thanks again Dennis.

  • 1 year later...
Posted

Did you get this figured out? I have a similar problem (2011 GMC Sierra). If I turn on the A/C shortly after a cold (or hot) start, the high speed fan is triggered after ~30 seconds, regardless of coolant temperature. It will run high speed for several minutes before eventually reverting to low speed (correct) operation and when running at high speed, the battery voltage will drop significantly.  In addition, the fans will continue to run high speed even at 60 mph, but will eventually switch off as they should. Refrigerant charge/pressure has been verified correct. I also replaced the high pressure A/C switch with no change in operation. Any help would very much be appreciated.

  • 3 years later...
Posted

Did anyone figure out how to fix this issue?

I have a 2007 Silverado 4.8 doing the same.   I was told it needed a compressor.  At this point I’m tired of throwing parts at it per mechanics suggestions.  
New compressor, condenser, orifice tube, hi and low pressure switches also took to Firestone to redo the refrigerant (pull vacuum and refill), new ACDelco water pump with thermostat, ACDelco temperature sensor.   And the cooling fans are on high all the time and the AC will not turn on.  

  • 1 year later...
Posted

I am having similar issues.. 08, 4.8L granted I did had a fender bender and minor damage up front passenger side but I don’t think it had anything to do with it.. I had the high and low pressure checked and my fan for my radiator keeps coming on.. replaced the pressure switch and don’t want to keep throwing parts at it. I did have some minor problems here and there like on long road trips sometimes the ac would get a little warm and then on the highway as soon as I give it a little gas or get a little heavier on the petal it started running cooler. Never had an issue with the ac besides the here and there.. but I also started having issues when I fuel up now it takes a bit to start ( super embarrassing) it runs fine and once started ( only happens after fueling up) starts fine any other time. Could they be related?

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Forum Statistics

    250.4k
    Total Topics
    2.7m
    Total Posts
  • Member Statistics

    342,758
    Total Members
    8,960
    Most Online
    Randy Ginoza
    Newest Member
    Randy Ginoza
    Joined
  • Who's Online   4 Members, 0 Anonymous, 1,858 Guests (See full list)

  • Latest Articles

  • Posts

    • Monday looks like a good day for the dealer to test an ac issue. Hopefully it all turns out good.
    • Paid $2.72 for E85 today.
    • Welcome back! No, it definitely doesn't pass the sniff test. Even "ceasefire" needs an alternative definition these days.    $5.29 at Kroger today
    • That makes sense, and I think you are describing the real product problem. Capturing data is the easy part. If the owner or technician has to manually dig through five minutes of millisecond-level logs, the product has already failed. The device would be at the ECM harness, not at the OBD port, so I agree that data retrieval and event marking need to be thought through carefully. The way I am thinking about the architecture is: The recorder itself should not depend on a phone, app, Bluetooth, Wi-Fi, or cloud connection to capture the event. It should always keep a local rolling buffer and lock the event locally. A button, phone app, or small cabin device would only act as an event marker. If the driver feels a stumble and presses the button 10–30 seconds later, the pre-buffer has to already contain the useful data. For data retrieval, the practical options would be a sealed service USB lead, Wi-Fi download, or a phone/cabin companion device. I would not expect the owner to remove the ECM-side module or work with raw files directly. The cloud or AI side would be for interpretation, not for capturing the event. The truck may have no connection when the issue happens, so the evidence has to be saved locally first. After that, cloud processing could help decode the data, compare it against baselines, and generate a readable report. For the first version, I would keep the automatic triggers conservative and objective: driver event marker bus-off error passive voltage drop / brownout device reset FIFO or queue overflow a normally periodic message disappearing side-to-side communication mismatch, if the topology supports that For “learning normal,” I agree with your point, but I would not want to overclaim it as automatic root-cause diagnosis at first. A realistic first step would be learned baseline comparison for that specific vehicle and operating condition. For example, a value would only be compared against similar conditions: RPM range load / MAP throttle position gear / vehicle speed coolant and oil temperature battery voltage AFM/DFM state, if decoded and validated Then the report could flag things like: this periodic message disappeared compared with its normal timing this value deviated from this vehicle’s normal range under similar conditions the same abnormal pattern repeated after the same type of event the anomaly occurred together with voltage, oil-pressure, misfire, or communication changes But I would still call that “abnormal pattern detected,” not “replace this part,” unless there is enough validated repair data behind it. So the intended product would not be “here is a huge log.” It would need to be an event package: what triggered the capture how much pre/post data was preserved what changed before and after the event whether the device itself reset, overflowed, or saw a bus error selected graphs around the event raw data only as supporting evidence From your perspective, what would make this kind of report useful instead of just another datalog? For example: What are the top 5 parameters or events you would want highlighted first? Would you trust a learned baseline for that specific vehicle, or would you prefer fixed thresholds? How much false-positive flagging would be acceptable before you stopped looking at the reports? What would a one-page report need to show for an independent shop to take it seriously? For misfire, AFM/DFM, oil pressure, or U-code complaints, what would you want the tool to flag automatically?
    • 2024 Silverado 2500 HD LTZ grille no camera Parts list   84603331 84913656 84913657 84913654 84913655 84911567 84911568 85646092 85646093 85797921 85797922   11570637  x10-15   grille/bumper bolts 11546500  x10      grille clips 11571006  x10      push/retainer clips 11546454  x6       nut retainers 11611609  x6       M5 bolts 11610700  x6       molding/trim retainers
  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...