In need of A/C help

sweet88gt

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Jun 25, 2005

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Venice FL

Apr 23, 2006

#1

• Apr 23, 2006

• #1

Ok, replaced compressor, all of the lines, low pressure cut off switch and I have no voltage to the compressor clutch. I jumpered the low pressure cut off switch and do not have any voltage to the compressor plug. What and where should I start to look?? My wide open throttle cut off realy had some issues with the wiring insulation coming off and I fixed that. Is there any other fuseable links or relays that I need to look into??

 

sweet88gt

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Jun 25, 2005

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Venice FL

Apr 23, 2006

#2

• Apr 23, 2006

• #2

Another idea is how do I check to see if the wide open throttle relay is ok?? I have 12volts on the red wire at the connector. I have 12 volts on the wire coming from the ac low pressure switch when jumper is installed. I just dont have 12 volts at the compressor plug. Is the relay a Ford only part??

 

HISSIN50

"How long does it take to get help in here?

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Apr 23, 2006

#3

• Apr 23, 2006

• #3

The relay can be bought at parts stores IIRC. I chose to ditch mine and simply use a Bosch SPDT relay and socket instead. IIRC, the common and NC terminals are closed at rest, giving your clutch current. When at WOT (approx 3.7 TPS volts +), the relay energizes, opening the connection at the common and NC terminals, thus cutting power to the A/C clutch.

Use your meter to check the WOT relay - using a test light can do goofy things to the relay (energize it), as I recall.

Good luck.

 

sweet88gt

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Jun 25, 2005

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Venice FL

Apr 23, 2006

#4

• Apr 23, 2006

• #4

Well, I back probed the relay and no juice. I had 12v from the battery. 12v from the low pressure switch, but nothing to the power wire for the compressor plug. I then jumpered the 12v source to the compressor plug just to see if I would get the proper voltage and I did. I will take it that the relay is nonfuctional. I will probably just replace it with the Ford part just to make it simple. Thanks.

By the way I have four wires to the relay. For clarification I have 12v source from battery,12v source from low pressure switch,sending wire to compressor plug, and what is the last wire for??

 

jrichker

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Apr 23, 2006

#5

• Apr 23, 2006

• #5

AutoZone wiring diagrams

http://www.autozone.com/servlet/UiB..._us/0900823d/80/16/71/3c/0900823d8016713c.jsp for 79-88 model Mustangs

http://www.autozone.com/servlet/UiB..._us/0900823d/80/19/59/5a/0900823d8019595a.jsp for 89-93 model Mustangs

http://www.autozone.com/servlet/UiB..._us/0900823d/80/1d/db/3c/0900823d801ddb3c.jsp for 94-98 model Mustangs

The following diagram is for an 88 Mustang.

 

willys1

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Dec 2, 2003

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Apr 23, 2006

#6

• Apr 23, 2006

• #6

A little off topic but what did you pay for the compressor?

 

sweet88gt

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Jun 25, 2005

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Venice FL

Apr 23, 2006

#7

• Apr 23, 2006

• #7

willys1 said:

A little off topic but what did you pay for the compressor?

Click to expand...

It was a reman and was $275.00. I havent had the A/C working in 2 yrs and in Fl it is a little rough. Just fired it up and blows nice and cold. I wish I would have done it sooner.By the way borrowed a buudys relay and checked the wiring all is ok.

 

willys1

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Apr 23, 2006

#8

• Apr 23, 2006

• #8

sweet88gt said:

It was a reman and was $275.00. I havent had the A/C working in 2 yrs and in Fl it is a little rough. Just fired it up and blows nice and cold. I wish I would have done it sooner.By the way borrowed a buudys relay and checked the wiring all is ok.

Click to expand...

Where'd you buy it? New or used?

 

sweet88gt

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Jun 25, 2005

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Venice FL

Apr 23, 2006

#9

• Apr 23, 2006

• #9

I got it from Advanced Auto and it was a new remanufatcured unit. An oem compressor would have been alot more but the reman has a warranty so I figured I would give it a shot.

 

willys1

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Apr 23, 2006

#10

• Apr 23, 2006

• #10

I need a new one thats why Im asking.

 

sweet88gt

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Jun 25, 2005

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Venice FL

Apr 23, 2006

#11

• Apr 23, 2006

• #11

When I did the a/c system I replaced everything. Last year I did a heater core and while I was in there I replaced the evap core as well. I replaced all of the lines and compressor today. If the compressor has let go it may need to be flushed or lines replaced. I found out that the orfice tube will get clogged by dirt and metal shavings from the compressor and cause problems. The orfice tune is part of one of the lines and should be replaced if it is suspect. Just a little of what I found out the hard way.

 

willys1

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#12

• Apr 23, 2006

• #12

nah the clutch's burnt out on mine!

 

sweet88gt

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Jun 25, 2005

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Venice FL

Apr 23, 2006

#13

• Apr 23, 2006

• #13

I would go to a salvage yard for that. Pick one up cheap there.

 

HISSIN50

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Apr 23, 2006

#14

• Apr 23, 2006

• #14

sweet88gt said:

By the way I have four wires to the relay. For clarification I have 12v source from battery,12v source from low pressure switch,sending wire to compressor plug, and what is the last wire for??

Click to expand...

The last wire should be a ground pulse from the puter at WOT. This energizes the relay to switch the power to the A/C compressor off (compressor clutch switch is on the NC terminal).

Crap, if I read it right, AZ's diagram shows that I am missing some electric fan wiring and componentry.