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A/C problem on 95 GT

  • Thread starter Thread starter mylilpony75
  • Start date Start date Jun 7, 2006
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mylilpony75

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Jun 7, 2006
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#1
  • Jun 7, 2006
  • #1
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???
 

The Green GT

No 13 year olds are safe around me.
10 Year Member
Jan 8, 2006
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Jun 7, 2006
#2
  • Jun 7, 2006
  • #2
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.
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
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Jun 7, 2006
#3
  • Jun 7, 2006
  • #3
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.
 
S

Synned

took tubgirl on a date and got banned
Mar 31, 2005
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Philly
Jun 7, 2006
#4
  • Jun 7, 2006
  • #4
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.
 

Methodical

15 Year Member
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Jun 7, 2006
#5
  • Jun 7, 2006
  • #5
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.

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
 

Blackened302

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Jul 21, 2005
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Jun 8, 2006
#6
  • Jun 8, 2006
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great info ^^^

might wanna check the high-pressure switch, too
 
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mylilpony75

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#7
  • Jun 8, 2006
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Ok, Round 2!

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!!
 
S

Synned

took tubgirl on a date and got banned
Mar 31, 2005
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Philly
Jun 8, 2006
#8
  • Jun 8, 2006
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Well did you try jumping the switches? I might have a picture hold on.

Here is the low pressure:


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

Blackened302

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#9
  • Jun 8, 2006
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how exactly did you jump the HIGH-pressure switch, synned? there are 4 wires--which two do you jump?
 
S

Synned

took tubgirl on a date and got banned
Mar 31, 2005
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#10
  • Jun 8, 2006
  • #10
Between blue w/ yellow stripe and green w/ orange
 
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mylilpony75

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#11
  • Jun 8, 2006
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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
 

mo_dingo

20+ Year Stangneter
Aug 26, 2003
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Jun 8, 2006
#12
  • Jun 8, 2006
  • #12
mylilpony75 said:
SYNNED-

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

Val
Click to expand...

Cold as ice
 

Methodical

15 Year Member
Dec 1, 2003
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Jun 9, 2006
#13
  • Jun 9, 2006
  • #13
I told you it would be the AC Cycling switch (or low pressure switch). Now where's my remy martin. Glad it's working. I love seeing a woman working her own ride.
 

fyassine

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Jun 25, 2006
#14
  • Jun 25, 2006
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Anyone have a picture of the high side pressure switch? I think I unplugged the wrong harness...
 

Methodical

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Jun 25, 2006
#15
  • Jun 25, 2006
  • #15
fyassine said:
Anyone have a picture of the high side pressure switch? I think I unplugged the wrong harness...
Click to expand...

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.
 
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Rjovi

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May 4, 2005
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Jun 26, 2006
#16
  • Jun 26, 2006
  • #16
Methodical said:
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.
Click to expand...

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.
 

kikboxr1

Founding Member
Jun 23, 2000
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Jul 18, 2013
#17
  • Jul 18, 2013
  • #17
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?
 

JJ95GTID

Active Member
Sep 22, 2003
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Jul 19, 2013
#18
  • Jul 19, 2013
  • #18
kikboxr1 said:
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?
Click to expand...


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.
 

kikboxr1

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Jul 22, 2013
#19
  • Jul 22, 2013
  • #19
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.
 

revhead347

Apparently my ex-husband made that mistake.
20+ Year Stangneter
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Jul 22, 2013
#20
  • Jul 22, 2013
  • #20
That stop leak is pretty terrible stuff. It blocks up everything.

Kurt
 
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