What should the pressures on the low and high side of the air conditioner read ?

low pressure side

YOU MORE LIKELY NEED MORE REFRIGERANT IN SYSTEM SOUND LOW FIRST HOOK A MANIFOLD GAUGE SET CHECK AC LOW PRESSURE SIDE AND HIGH PRESSURE SIDE.LOW PRESSURE SIDE SHOULD BE 34 PSI AND HIGH SIDE SHOULD BE 228 PSI.

First, I would check that the a/c compressor is on at idle.
Then, I would check that the fan goes on.
After, that I would check that the plumbing is getting cold on the low side. If it is not, then I would look for causes for that, including but not limited to the r134a refrigerant pressure being too low.

It should read 25 psi to 45 psi on the low side when the a/c compressor is turning, which is normal.

If it reads 75 psi to 100 psi or higher and the a/c compressor is not turning, then there is a problem.

The a/c compressor could be wearing out (its pistons that is) and causing the pressure to not be high enough at idle speed.

Hi, determine if your car uses R134 or R12 refrigerant. You will notice screw type connectors on the both the High Pressure Side and Low Pressure Side lines in models using R12 refrigerant. R134 compatible models have quick connect valves on both sides. Models made before 1995 may use the old R12 refrigerant. If this is the case, you must have your Chrysler's air conditioning system retrofitted to use R134 refrigerant. Mixing R12 and R134 refrigerants is dangerous and may cause damage to your vehicle. Check your air conditioning system pressure using an automotive air conditioning pressure gauge. Keep in mind that in order to get an accurate reading, the air conditioner has be turned on the coldest setting with maximum blowing power. Remove the Low Pressure Side port valve cap and set it aside. The location of the port varies, but it is usually in front of the engine block. Attach the refill hose to the port on the Low Pressure Side of the air conditioning system. The Low Pressure Side port is smaller the High Pressure Side port. Because the ports are different sizes, the refill kit hose should fit only on the Low Pressure Side port. Additionally, the High Pressure Side port will usually have a red cap or be marked with an H or the word High Allow the air conditioner to **** the refrigerant out of the can by slowly turning the valve on the refill kit hose. Pay attention to the way you hold the can. Most kits will have you hold the can upright when you recharge the air conditioning system. It may take as long as 10 minutes to empty a single can. Turn the valve to the off position and remove the refill hose from the port. Recap the port before closing the hood. Let the air conditioner stay on for at least 30 minutes. This allows the refrigerant to move throughout the entire system.
Take care

very high pressure suction will cut by high pressure sensor to command compressor on/off, release refrigerant, check condenser clogging, filter drier expansion valve, or accumulator and orrifice filter and tube

BOTH High and low readings should be checked to have a better idea of what is going on with an AC system but based on the limited information… the compressor is not engaged or is not pumping. Below are some things I would check;

1. Check the high and low gauge readings with the AC on & set on MAX/Recirculate, middle vents with the engine at 2,000 RPM’s, blower speed on high.

2. Check the vent temperatures with a thermometer from the middle vents, far right & far left vents?

3. What is the outside temperature at the time the readings were taken?
4. Check to see if the condenser fan blowing strong?

5. Notice if compressor clutch is cylcling excessively.
Could be overcharged, not enough air going across condenser fins, compressor not pumping sufficiently… BOTH gauge readings are really needed to get a better idea.
Below are normal car AC pressure readings with 134A.

Normal readings on high and low side with AC OFF (static pressure) – Depends on outside temperature, but normally is between 80-105 PSI

Normal low side reading with AC on high speed and MAX & engine at 800-1000 RPM’s – Ranges from 25-35 PSI

Normal high side reading ranges from 200-350 PSI

Don’t assume that if adding little Freon is good that adding a lot is better! Overcharging just a little can decrease the performance of the system and possibly damage the compressor

Thank you for using fixya and good luck, keep me posted. Be glad to help you get your A/C running again soon.

Is that your static pressure readings??? If that is your static pressure readings that's good. When the engine running and fan on high and a/c compressor clutch engaged you should have 25 to 35psi on your low side and 200 to 350psi on your high side. If the clutch is engaged and that is your readings, replace your a/c compressor. Keep me posted, be glad to help.

from the compressor there is two lines coming
from the back side, follow the line that goes
in to the front condenser thats your low side.


G

Can't go by the pressure. Ck the large lone coming out of firewall, should be col. Small line at ac condensor in front of radiator should be hot.

Static pressure on high side probably 80psI Running 30 on the low side and 1130. will vary depending on oiutside temp Hope this hekoped

Black Cap to your left, right up front as you open the hood. Next to the Engine Coolant cap.