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Discussion Starter · #1 ·
as the title says I can only get the compressor to engage above 24 or 2500 rpms???

I've recently changed:

Tstat, temp sensor, large fan motor, fan control module

as well as tested the pressure switch by jumping it (no compressor)

and I CAN get the compressor to engage by a direct battery connection.

freon pressure is about 25 (I think...i may be remembering that wrong...)

(also checked all the fuses inside and the 30ampers on the battery cover....and wiggled those too)


please advise...
 

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Discussion Starter · #3 ·
maybe its low then....

but shouldn't i be able to jump the low pressure switch and get it to engage?
 

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The reason that switch is there... Damage occurs to the compressor when it is turning, and not enough pressure in the system.
Step one. Pull a vacuum. Step two. Charge with 700 grams of freon.
Step 3. Enjoy your air conditioner. :)

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Discussion Starter · #5 ·
I'm confused....


when I've done AC work in the past...I've had to jump the low pressure switch in order to get the clutch to engage....for it to take the freon...

am I missing something here?
 

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Discussion Starter · #7 ·
please dont take this as an argument....

if low freon is the issue, why would jumping the pressure switch NOT make the clutch engage?

I just like to understand whats going on with things
 

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Yes, if your clutch will engage that is a good sign. That is one of the first steps in diagnosing an air conditioning problem. But, if you run the compressor with not enough freon, it will not cool properly. And it will damage the compressor due to lack of oil.
So, you are very close to having your problem fixed. The next steps that are necessary is to put the proper charge of refrigerant in the system.
You are at the end of the diagnostic flow chart. :)
Very, very, close grasshopper!
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Discussion Starter · #9 · (Edited)
but my clutch will NOT engage.

it only engages above 2500rpm and when it does...its cold and works great. just not at idle (below 2500)
 

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FYI, shorting the switch to get the clutch to engage just proves the clutch works, not the compressor.

Silly question, when was the last time that you had the freon completely drained and reloaded?
 

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Do your radiator fans come on when you turn the a/c on even if the compressor doesn't engage?

Also, fuse s180 is a common problem with the a/c. It is the leftmost of the 3 small fuses on the fuse panel above the battery. Try wiggling the fuse in its socket and see if the compressor engages.
 

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Discussion Starter · #12 ·
yes...fans operate correctly (had to replace the larger ones motor).

30amp fuses on the battery check out ok and no luck wiggling them.
 

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So when you push the a/c button the radiator fans comes on right away even if the engine is cold?

I suspect you may have a bad connection somewhere, either supply or ground. The fan controller operates the a/c clutch as well as the fans. The fan controller is connected to the ECU and may be set to cut out the cooling fans at 2500 rpm, figuring that the car is moving and the fans are not needed. With a bad connection there may not be enough current flow to operate the fans and a/c clutch at the same time. When the fans cut out, the compressor gets a higher voltage and engages.

You could test this by disconnecting the connector at the a/c clutch and measuring the voltage when you turn the a/c on. You will probably see a voltage even though the clutch isn't engaging. Another thing to try would be disconnecting the radiator fans and checking if the clutch will engage.
 

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Okay, I know one sensor that you can jump off to try to get your AC to work. There is one sensor in front of your coolant temperature sensor. It is a two pin sensor connector. It is called the AC thermal cut out switch. (F163)
This switches off AC clutch at excessively high coolant temperature. This switch is known to fail, and it will cause nightmares trying to diagnose your air conditioning system. Now, if your air conditioning system has the proper charge, this might just be your problem. It might help, if we knew what year your car was also.

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My A/C wasn't working except when driving when I bought Iggy (found out on test drive). The lot I bought her from sent her to their mechanic who said it was one of the fans not kicking on. The lot agreed to have it fixed for me, so I got her. When I left her with the mechanic, it turned out it wasn't the fans; but whatever runs them so I ended up with new fans as a bonus. I think they said it was the relay? Can't remember, been too long. Whatever it was, they said it was what told the fans to kick on and off. That was before the self repair bug bit me so I wasn't really paying attention. All I know is that she's worked fine since.


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No, heat and a/c don't really have anything to do with each other in these cars. Have you tried any of my suggestions from message #13?
 

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You should first check alternator voltage and map sensor, they could be an issue. You should also be sure about freon pressure and do not use R22 compressor as government has banned it. If these all don't work, then go for some competent ac repair vero beach technician who would do the job effectively and efficiently.
 
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