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Discussion Starter · #1 ·
Hey doodz...

Just got me a set of hoses and adapters for my refrigerant gages to allow me to look at and service automotive a/c...

Here's my question(s):

What pressure should my Hi/Low switch cut in and out at?

What should my pressures be at idle?

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I've been toying with installing a condenser fan to avoid my compressor cycling on and off so much at idle which led me onto this persuit.

My compressor will cycle on, the low side pressure will drop to about 15-16 psi and then it'll cut out, until the high side drops a bit then it'll cut back in and repeat the process, now, this is with the interior blower fan on low. If I turn the fan on high, the low side pressure will stay at about 25-26 and the compressor will continue to run without cycling off.

I don't know about you, but I don't wanna leave the fan on high and freeze myself to death but also don't like to be sitting at a light with the fan on low and feel the air get cold then warm again with the cycling of the compressor.

Last question:

Do these pressures/actions of the compressor seem correct?
 

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Discussion Starter · #2 ·
PS: My bad, this is on my '96 with R134A.
 

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all i could fine in my fsm ( 99-2002 ) , but they may help

manual tranny:low pressure on 30 plus/minus 4 , off 25.6 p/m 3
high pressure on 341 p/m 28 , off 426 p/m 28

auto tranny : low pressure on 27 p/m 4 off 25.6 p/m 3
high pressure on 341 p/m 28 off 426 p/m 28
condenser fan medium pressure control on 213 p/m 14
off 156 p/m 17

one thing i have read is the ac high pressure will be 2.3-2.5 times the amb temp , if its 100d then look for the high pressure to be about 240.
the thing is , the temp under the hood is much higher than outside temp.

i think if a person could shield the ac compressor from the exhaust man and 180d radiator temp with some kind of shield to get outside cooler air to the ac compressor i think compressors would last longer with the lower high side pressure because of the lower temp.

you should use the above numbers as a guide as yours may be different , i doubt it thou.
 
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