A/C problem on 95 GT

Discussion in '1994 - 1995 Specific Tech' started by mylilpony75, Jun 8, 2006.


  1. mylilpony75

    mylilpony75 New Member

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    A/C fans blow hot air. Put refrigerant in... Discovered it was now over-charged. Compressor does not kick-over. evacuated the system. refilled per directions. Sitting at 25, no cool air--no compressor. What is going on? Don't want to replace compressor ($$$) unless I truly have to. Anything else I can check???
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  2. The Green GT

    The Green GT No 13 year olds are safe around me.

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    Check the pressure switch. It will cut off the compressor when the coolant is low. They go bad sometimes and just make it cut off. Try jumping it.
    #2
  3. HISSIN50

    HISSIN50 "How long does it take to get help in here? SN Certified Technician

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    I would start tracing the power circuit if your clutch isnt engaging (if it isnt, it sounds like you are low on charge. You have to jump the AC clutch to charge an empty system).

    Courtesy of S&2B's (site host) and TMoss (diagram author) is this diagram.

    Good luck.
    #3
  4. Synned

    Synned took tubgirl on a date and got banned

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    First see if there is voltage getting there at all, at the plug on the bottom of the compressor.
    Hissin should be able to help you get to the bottom of it from there. ;).

    I have GREAT troubleshooting diagrams for this, first see if theres voltage.
    2nd Easiest thing would be to jump the switch by the passanger firewall, the low pressure switch (on a canister), then try jumping the high pressure switch on the line by your radiator.
    #4
  5. Methodical

    Methodical Active Member

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    First of all if you think you overcharged it then you need to release some to get it between 25-45 lbs. so get a gauge to check the pressure. You can get gauge from your local auto parts store. You have to test the pressure of the system with the AC running so in order to get the AC compressor to kick on you will need to install a jumber on the AC cycling switch harness (see how below)

    But aside from that, I guarantee it's you AC Cycling Switch. Here's how you test it. Look on the passenger side firewall and you will see the receiver/dryer. On top of it is a twist on switch with an electrical connector. Unplug the electrical connector and install a jumper wire on the electrical connector and then turn on the AC and the AC clutch will kick on. If the AC clutch kicks on then most likely the AC Cycling Switch is bad. Now, the Ford Service Manual states to check the pressure of the system if the above happens and if the pressure is ok, replace the switch. To check the pressure, you need a R134a manifold gauge or you can use one of those recharge kits from you local parts store with the gauge to check the pressure. But again, I guarantee its the AC Cycling switch, which cost me about $33.

    This was the first part I replaced on my new 95 Mustang (I was out of the warranty mileage) in the summer of 1996 after I had just purchased the Ford Service Manual so the book's step by step diagnostics paid for the book.:D

    If your AC was working with no problems, such as the AC clutch was not cycling on and off, then most likely it's just the switch.

    Now, if your AC clutch was cycling on and off constantly before the AC quit, then your system is low and needs a recharge, which could indicate a possilbe leak in the system. But you indicated that you charge (maybe overcharged) the sytem so again I think it's the switch

    Peace :rolleyes:
    #5
  6. Blackened302

    Blackened302 New Member

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    great info ^^^

    might wanna check the high-pressure switch, too
    #6
  7. mylilpony75

    mylilpony75 New Member

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    Ok, Round 2!

    :hail2: Thanks guys! I did "jump the compressor", it runs great just connected to the battery, but there is no voltage in the wire leading to it. WHAT IS THAT??? Thanks for the other stellar advice, too. However, I am a stereotypical blonde female. I understand the concept of checking high and low pressure switches, and even clutches. But, if you can tell me what I am looking for (shape/color/etc) and where to find it, that would be great!! :p
    #7
  8. Synned

    Synned took tubgirl on a date and got banned

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    Well did you try jumping the switches? I might have a picture hold on.

    Here is the low pressure:
    [​IMG]

    And the high pressure is just a green connecter with 4 wires going into the a/c line near the radiator.
    #8
  9. Blackened302

    Blackened302 New Member

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    how exactly did you jump the HIGH-pressure switch, synned? there are 4 wires--which two do you jump?
    #9
  10. Synned

    Synned took tubgirl on a date and got banned

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    Between blue w/ yellow stripe and green w/ orange
    #10
  11. mylilpony75

    mylilpony75 New Member

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    SYNNED-

    Hey! Thanks! Low pressure switch? That was exactly the problem! You're the man! 17 dollars later, she's ice cold!

    Val
    #11
  12. mo_dingo

    mo_dingo Well-Known Member

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    Cold as ice
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  13. Methodical

    Methodical Active Member

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    I told you it would be the AC Cycling switch (or low pressure switch).:rolleyes: Now where's my remy martin. Glad it's working.:nice: I love seeing a woman working her own ride.:p
    #13
  14. fyassine

    fyassine Founding Member

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    Anyone have a picture of the high side pressure switch? I think I unplugged the wrong harness...
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  15. Methodical

    Methodical Active Member

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    No but it sits in the AC line on the passenger side where it goes to the condensor between the headlight and upper radiator hose and it should be a green connector. I'm sure someone will provide a picture though.
    #15
  16. Rjovi

    Rjovi Member

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    yep, and you can't miss it..really. I just had the A/C problem, mine was because the system was too low, but we also jumped the swtich on the firewall first.
    #16
  17. kikboxr1

    kikboxr1 Founding Member

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    I apologize for reviving an old thread but that seems better than opening a new thread.

    My question is, how do you replace the low pressure switch? Does the system need to be evaporated by a shop first?
    #17
  18. JJ95GTID

    JJ95GTID Active Member

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    It's a schrader valve. Just unplug the connector and then unscrew the switch. You'll hear a little bleeding out of the line when you get to the end. Just be quick about it and it won't leak out enough to cause problems.
    #18
  19. kikboxr1

    kikboxr1 Founding Member

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    Thanks JJ.
    I actually found after some troubleshooting that the system was out of refrigerant. I charged it with the stop leak added R134a so we'll see how long it lasts.
    #19
  20. revhead347

    revhead347 I have face herpes.

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    That stop leak is pretty terrible stuff. It blocks up everything.

    Kurt
    #20

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