A/c warm low and high side pressures wrong

Two fittings close together. The small one closer to firewall is the low side. The large one close to condenser is high side. Orifice tube is in the line and drops pressure. HOW TO RECHARGE THE AC FOR CHEVY TAHOE HOW TO REPLACE ORIFICE TUBE

Sounds like the fittings are reversed.
With the compressor running, the low side should drop below zero then climb to 60 or 80 psi as you add freon.
You would need to jumper the low pressure switch to engage the compressor clutch to add freon. The compressor must be running.

With the wire to the compressor unplugged, see if 12 volts is present at the plug. If voltage is present, then check the terminals on the compressor clutch for continuity. ( voltage meter in beep mode) Volt meter will beep if clutch coil is good, no beep, clutch coil is bad. Also low Freon pressure will disable clutch via low pressure switch at the accumulator. Always check pressure and add Freon to low side(large tubing) A freeze hazard and explosion hazard (high side, small tubing) exist when handling Freon. Wear safety glasses and be careful. Also cooling fans should run continuous when A/C is on

It is probably low on freon. The low pressure switch will turn it off to protect the compressor because it needs the freon to circulate the oil. Hot-wiring it defeats the purpose of the low pressure switch and runs the compressor without oil. If you have not already destroyed your compressor by hot-wiring it, you can probably get it working better by charging the system.

Hello, It can be the clutch but you need to test the residual pressure in the system as is. The clicking sound indicates the clutch is being switched off and on by the pressure switches. The smoke and smell can be the Freon escaping from a hole in the lines. Or the last gasp of the Freon created ice deposits which melted on the exhaust pipes and is now gone.

A quick explanation of the pressure switches and clicks. You have both a low and high pressure cutoff switch, the ideal pressure is theoretically in the middle of these 2 pressures and kepts the clutch running the longest. With too much Freon the pressure gets too high and the high pressure switch cuts off the clutch; with too little Freon the low pressure switch cuts off the clutch.

You need a tool to test pressure. The low pressure switch is on the freon line close to the black oblong cylinder. If you unplug the wire to this switch and make a U shaped coated jumper wire, you can make the clutch engage by inserting the wire into the connector while the engine is running. Do this for less than a minute if you are not prepared to add Freon, then remove the jumper.

You now know the problem is low pressure if the clutch turns on. Remember to have the dash controls set for the A/C. If the clutch did not engage, check your fuses, then blame your clutch.

Many of the autoparts stores have tool loaner programs. Check with the parts store for the A/C clutch and what tool is needed to change it. There is some room under the hood of a Grand Marquis and it may be possible to replace the clutch without removing the compressor or lines.

If the problem is low pressure and not the clutch, you must find the leak. Get a can of Freon with leak detector, jump the low pressure switch and add the Freon to the oblong tank by the Firewall.
Then repair the problem identified and purge and recharge the system. The autoparts stores loan out the Vacuum dryers.

Have you checked the low side and high side pressures? The compressor might be bad. Does one line to the compressor get cold and the line coming out get hot?

I'm assuming that's the high side pressure reading. It sounds like you don't have enough refrigerant in there still. Depending on outside temperature the high should be around 130-150 and the low side between 25 - 30 or so with the compressor clutch engaged. Once you connect the can to the low side you'll have to start the car and turn the a/c on to get more in there until the pressure readings are correct.

do you have gauges hooked to vehicle to read a/c pressures?? it is cycling because low side is dropping too low. this is because we aer low in freon or there is a blockage. need to be able to read pressures as just adding freon if you have a blockage can cause compressor to blow the lines off it. a blockage would most likely come from the orifice to stopped up. but if this is plugged up then we need to find out where the debris came from to block it.

The ac system may need freon added,if the system is low,or out of freon,it will not allow the ac compressor to come on.

kavalbe: Servicing the A/C is sometimes not as simple as adding some freon. Ideally, it requires both high and low side gauges to monitor pressures when charging a system. Additionally, many systems today don't us anywhere the amount of freon that the old sytems did consequently it is not uncommon to find cars coming into shops with the complaint of A/C systems not cooling and all we find wrong is that the customer had over charged the system.
Your vehicle depending on whether it has Automatic Air or not has two different capacity specifications.
Automatic A/C (2 lbs ) Manual (1 lb 1.14 oz )

Unless you have a means of measuring the amount going in, it is difficult to charge the manual system accurately.
In my shop, I always empty the system, pull it into a vacuum and then set my machine for the exact amount.
When the system is being emptied, I will record the amount which had been recovered to let the customer know if they have over charged or under charged the system.
The pressures will tell if there is a problem with the orifice tube or compressor or other problems.
This may be a situation where you may either need to invest in a set on manifold gauges to let me or someone here know how the system is reading, OR bring it into a shop and at least have them diagnose the problem to find out if it is something over your head.