The pressures are dependant upon many things. Ambient temperature, blower speed, charge level, radiator fan speed, etc...
There is no one set pressure for the low side port.
How many psi should there be at the low side service port? Alldata says the
> system holds 1.74 pounds of R134a. They don't give the operating pressure.
>
> Also, I noted that the low side pressure fluctuates. Could that indicate a
> problem somewhere?
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> Thanks.
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