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How to Jump the 3 Wire AC Pressure Switch on Your Own – What You Need to Know

How to Jump the 3 Wire AC Pressure Switch on Your Own – What You Need to Know

There are many factors to look out for when you buy a car. Is it comfortable? Is it vehicle safety? Is it the engine’s power? Most people choose comfort above all else which is quite understandable. One thing that contributes to the comfort car owners and drivers experience when in the vehicle is the air conditioning. The air conditioning cannot be ignored especially in the summer when you really feel the heat and you can go for more cool inside the car while traveling. But besides helping make you comfortable, did you know that the air conditioning also has some things in store that would also contribute to the performance of the engine. The operations lying behind the air conditioning system is the AC Pressure Switch. All is well with the pressure switches working perfectly fine. But there may come the time that you will find some faults with the switches making it very uncomfortable inside the car. Jumping 3 wire AC pressure switches on your own may be what it takes to fix this inconvenience. 

Auto Repairs Are EXPENSIVE


But before we get into it, there are several things that you do have to know about the AC System and the Pressure Switch.


In definition, the AC Pressure Switch is a safety switch located behind the air conditioning system. The system has two pressure switches namely the high side pressure switch, and low side pressure switch, both surveil the AC system in case there would be pressure problems that can in turn damage the compressor. Also the pressure switch monitors the refrigerant which is the one responsible also for reducing the heat in the vehicle. 


Another purpose of the pressure switches is to ensure that the AC System functions properly. The pressure switches are the ones responsible for protecting the air conditioning system from being damaged. The system has five main parts that have major roles to play in order for the whole huddle to work perfectly. These five are namely the following:




This part of the whole air conditioning system is unarguably the most important part of the whole. The cool air that you enjoy inside your vehicle is the byproduct of the compressor. How does it do that? Basically, the work of the compressor is to put pressure into the refrigerant in order to cool the air. It moves the air into the condenser. It also has several features including sensing temperature shifts in and out of the vehicle and monitoring the temperature inside the car. 




The condenser is mostly famous for its nickname, the min-radiator, taking credit to where it is located, near the radiator. The compressor works together with the condenser. While the compressor does its job with applying pressure to the refrigerant, the condenser controls the temperature and pressure that comes from the refrigerant. One more thing about this component is that the condenser is also in charge of moving the already ventilated liquid refrigerant to the accumulator.




The accumulator is not a standard feature in some vehicles but this is also an important component in the air conditioning system. The accumulator/receiver or dryer works to separate the gas from the liquid in the system. This part of the job is very important since the compressor is not for handling the liquids. It will get ruined once acquainted with liquid inside of it. Also, the accumulator speaks for itself. It accumulates excess refrigerant. It filters debris and removes moisture in the system, regulating the refrigerant that enters into the evaporator. 




This component is also known as the orifice tube. This is located between the condenser and the evaporator. It works together with the condenser to monitor pressure. It ensures that only the safe refrigerants go into the evaporator.




This one gets more attention than most of the components that function behind the air conditioning. The evaporator is located just behind the dashboard, cooling the air with the refrigerant which in turn  is blown into the car cabin.


How do you test a 3 wire AC Pressure Switch?


Unlike the other systems in a car, the air conditioning system has a sensitive part that could cost you a lot in the long run once they start to fail.Although, this system is one of the splendid resources that car owners everywhere enjoy, it may be quite problematic if it is left unchecked. So how does one test or jump 3 wire AC Pressure Switch? Fortunately, you do not have to be a total know-it-all or expert in the biz to be able to repair an AC Switch. There are just simple ways you can absolutely do all by yourself in order to keep the AC functioning again. Interested? Read on.


First off, the testing. How do you know if your AC Pressure Switch is bad?


Troubleshooting covers a large part of owning a vehicle. If you are doing this all by yourself, there are plenty of visible sources to know whether something is wrong with your car. When the AIr Conditioning System starts to deteriorate or malfunction, it usually gives off signals or symptoms that you can then troubleshoot to know what is the matter with your car. This way you can easily identify what things you have to do in order to address the issues immediately to avoid further damage in the vehicle. Here are some of the symptoms you should look out for in order to test the AC Pressure Switch: 




Normally, the air conditioner turns itself off once it reaches the ideal temperature for the vehicle. Defective AC Systems usually has this dilemma wherein the air condition starts to switch itself off in short intervals. If this happens frequently during your rides, you can make the right guess, there is something wrong with the system.




If either the pressure switches are defective, then the whole system will be unable to serve its purpose to produce cool air. If this is not the case, you may notice that the car takes longer time to cool which will mean that there is a definite problem that needs to be resolved with the vehicle. 




Continuous switching between on and off of the AC Compressor can result in a switch failure which can then prevent the AC compressor from functioning optimally, or worse, it may not be able to function at all. The compressor is responsible for distributing the refrigerant through the whole system and so as these issues start to arise, the Air Conditioning System will not be able to deliver the service it is supposed to render to the whole engine.


Jumping the pressure switches also has its own downsides as this could result in the ruin of the compressor. So you must consider the aforementioned symptoms before you decide to commence the jumping. Once you are able to detect these symptoms in the air conditioning system, you can now start jumping the 3 wire AC Pressure Switch. These are some of the simple procedures you could apply to the engine’s AC System by yourself in order to jump the pressure switch successfully. 


  1. The first step has to do something with the PCM fuse or the Power-train Control Module. The PCM is a piece of the clockwork in an engine that is very valuable. It is also expensive to replace. The power-train control module is the part in control of many of the workings in the vehicle such as the ignition system, emission system, fuel functions and these sorts. It also has something to do with the automatic transmission system used in most cars these days. Be careful in pulling out the fuse. Once it is out, you can start doing the little needed repairs.


  1. Next thing you have to do may sound a bit complicated. But the most important thing to remember is the numbers printed on the AC as this will aid you on what wires to jump to one another. Bypass the 3 wire AC pressure switch through B1 to B4. This action will help your compressor maintain its good workings. 


  1. Step three is not that complicated but it is delicate. If you have not followed the first steps mentioned above, please do so, as jumping to the third step without following step one and two could result in damage in the compressor. If you followed the directions carefully, the third step is to connect the charging connectors. After this, pull back a bit and wait for the charge to complete and for the coolant to fill. 


  1. Once the charging is complete, open the gas valves. Then you may enjoy your fixed AC and get that comfort of a nicely working AC System.


Can you bypass AC high pressure switches?


To simply answer this question, yes you can bypass the AC high pressure switches. But first, do identify your reason for doing so. Make sure that you are going to bypass the right issue only temporarily then you can go ahead and replace it. There are possible issues that may arise after bypassing the AC high pressure switch which may be caused by a poor performing condenser fan motor. So how do you bypass the high pressure switches on the air conditioner? You can do simple things such as (1)simply locate the air conditioning pressure switch and make sure disconnect the battery cables that are negative; (2) remove the switches- the switch electrical connector and the high pressure switch; (3) put in the new switch and reinstall the electrical connector switch you put off in step two and reconnect the negative battery cable; (4) final thing to do is to test the AC. 


How do you jump a low pressure switch?


The reason for jumping a low pressure switch is to test the circuit. What does the low pressure switch do? The low pressure switch of the air conditioning system in the engine is the one preventing the relay from distributing power to the air conditioning compressor. One thing to always put in mind is to nor jump the low pressure switch while the engine is running. If you do so, you may do it for only a few seconds. This action, when taken, may lead to the damage of the compressor. To jump a low pressure switch, start the motor and then put the controls in maximum. Unplug the connector latched to the cycling switch then connect the two female ports on the removed connector. Observe the compressor and see if it works.




The air conditioning system or the AC System in your car’s engine is one that has so much to do with the comfort riders and drivers everywhere are looking to experience. Imagine going on long vacations under the heat of the sun without the AC to back you up with cool breeze inside your car cabin against the humid weather, not a pleasant sight nor a fun adventure. But with you mastering these how-to's on how you will jump, the air conditioning pressure switch will surely aid you in your destinations. There are various reasons why jumping the AC pressure switch may be the right way to go for you. 


Make sure that you do a careful job on troubleshooting your engine before you do anything. It all boils down to you having keen eyes and a great deal of effort on taking care of your ride. The symptoms that the engine shows for the faulty air conditioning system is one that you should not overlook. You do not really have to be an expert or a mechanic to be able to do quick fixes in your car. But, you do have to be careful with your meddling with the car’s cooling system since it can cost you the compressor. Nevertheless, you do have the choice of handling it yourself or taking things to the mechanic. Going to the professionals is also convenient. But the former gives greater satisfaction don’t you think?