A/c Issue

Discussion in 'SN95 V6 Mustang Tech' started by RedWings44, May 20, 2012.


  1. RedWings44

    RedWings44 Member

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    I'm sure many have seen this, so I feel safe in asking about this here.

    My A/C will not blow cold air, nor will the regular vents. We tried a can of refrigerant that you can get from the store, but when we placed the hose of the can on the valve, the pressure gage shot to the red before we could put anything in. Not the extreme red, just the beginning of it, but it was never-the-less in the red. We tried this last year, so I don't remember the exact measurement the game read.

    Does this mean I need to replace my compressor? Or do I simply need to release the pressure? I'm not really a car person in terms of know-how, so I thought I'd start here before I started researching parts I may not need. Also, it is about 85 today and only going to get hotter for the summer lol. Anything would be great.

    In case it matters, I have a 1998 3.8L V6
     
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  2. wmburns

    SN Certified Technician

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    Working on AC systems can be hazardous when you don't know what you are doing. For example, did you note if the compress was turning at the time? If not turning, the gauge will always read in the "red".

    It's not possible to add Freon unless the AC compressor is actually engaged and turning. If the AC clutch is not engaging at all, then THAT is where the trouble shooting should begin.
     
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  3. RedWings44

    RedWings44 Member

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    I don't really even know what that (AC clutch)..but we did try it with it running and not running (on AC that is)...is that an easy fix?
     
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  4. wmburns

    SN Certified Technician

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    If you don't know what an AC clutch is, consider using the services of professionals. Especially since you are looking for "easy" fixes!

    If insisting, check the fuses in the engine bay and driver's kick panel. Are they all good?

    Next test for +12 volts at the AC low pressure switch with the AC on and the key on. Post. If no voltage, the problem is in the AC mode controller in the dash.

    If there's voltage at the low pressure switch, additional trouble shooting will be needed. A set of wiring diagrams will be a plus. Do you have a Volt-Ohm meter and are you willing to use it?

    If interested in getting a set of wiring diagrams for yourself, I maybe able to help. PM if interested.

    99-04 fuse panel layout:
    http://Please do not link to extern...r-swap-wont-fire-please-help.html#post2669271
     
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  5. RedWings44

    RedWings44 Member

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    Thanks...ya, not as much easy fixes as much as DIY/cheap fixes. I do believe I have such a meter. Anything else, feel free to post it. Idk when I will actually get to this project, but hopefully sometime soon.
     
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  6. RedWings44

    RedWings44 Member

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    Ok, so (after examining your post in further detail) you are saying that my problem is likely some sort of electrical issue and not something I'd have to replace within the engine?
     
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  7. wmburns

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    That is the purpose of the tests to confirm what's the real problem. It could be anything from a bad AC clutch, bad low pressure switch, bad fuse, bad mode controller, bad CCRM.

    There is no elevator to success. You have to take the steps.
     
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  8. RedWings44

    RedWings44 Member

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    I see. I will let you know when I actually get the chance to look. It may not be for a while though. Thanks for the help
     
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  9. RedWings44

    RedWings44 Member

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    Update:
    Today I checked the fuses and they were all fine. The owner's manual didn't say there were any AC fuses under the hood so I didn't check there. All the fuses I did check had to do with both the AC and the heater...well my heater works better than any car I have ever seen. I often turn it down on days where it is even below 25.
     
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  10. wmburns

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    Monitioring until the rest of the tests requested are posted. Until then, nothing for us out in Internet land to do.
     
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  11. RedWings44

    RedWings44 Member

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    Thanks I appreciate it. I'm only 19 and the car belongs to my dad. He likes to be involved in all the work on vehicles we have...since we replaced the fillerneck grommet about a week or so ago, the Mustang is now pretty much at the bottom of his priority list...so the other tests may not be soon sadly. Plus, for something like this (where he has the tools necessary), I wouldn't do it myself anyway lol
     
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  12. RedWings44

    RedWings44 Member

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    I am back after a long hiatus. Kept getting busy and forgetting about this but I finally was able to run a few of the tests. OK here is where I am at so far, the AC clutch does not engage but I can turn it with my hand so I know it isn't stuck. All the fuses look good as well. I haven't run any of the electrical tests on it yet. I heard that it is possible that the safety has engaged on the clutch/compressor due to low refrigerant (sp?) thus not allowing it to spin. I've seen someone show how to bypass the safety so they could refill it themselves. It seemed sketchy but what do you think about all of this wmburns?

    ...or anyone for that fact actually
     
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  13. RedWings44

    RedWings44 Member

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    Update: I took it in for a free AC inspection today. They said it is a bad switch on the back of the compressor. They said they would replace it and fill it with freeon (sp) for around $100. I think I got lucky but we'll find out when I get the car back tomorrow morning.
     
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  14. RedWings44

    RedWings44 Member

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    Update (again): It worked excellent when I picked it up. It was not quite hot enough to need it but I couldn't wait for a hot day to try it out. The next day (yesterday) I got the chance. However it was blowing warmer than when I picked it up. Looked under the hood and sure enough I see the compressor cutting in and out intermittently telling me there was a leak in the system somewhere and I was low on refrigerant. I took her back in today. Hopefully they will find it and be able to fix it.
     
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  15. RedWings44

    RedWings44 Member

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    Final update (fingers crossed): The second issue was a leaky Schrader Valve on the low pressure side. Cost $45 to get fixed. I'm happy. $145 to repair an AC is still a hell of a deal if you ask me. I got quite lucky with my issues. I hope this thread helps any others who may need guidance in possible things to look for as far as issues. Also, thank you wmburns for your assistance and patience with me
     
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