You need to consider the chance of a blend door problem. This condition has a few possible causes: the AC system could be low on refrigerant, an electrical problem … The TXV is very efficient and is designed to tightly control liquid refrigerant from spilling out of the evaporator. Take … The red, high side gauge is used to measure the high pressure side of the a/c system. There are too many variables. Windows can be open. There is no magic answer for this question though. That's where the manifold gauge set comes into play. This is because electric condenser fans are fixed in speed, and will not compensate for high engine RPM. Author: Mike Thomas. What do you think is wrong? It can be used for recharging refrigerant, or to diagnose an a/c system based on pressure readings from your gauges. Low blower speed will reduce heat load on the evaporator to the point where compressor cycling can occur. It goes something like this. Each refrigerant has it's own static pressure at every corresponding degree in temperature. Tachometer Display Failure In most cases, the hose intended for the low pressure service port is blue, and the hose intended for the high pressure service port is red. With R12 systems, high side pressure is usually 1.8 to 2.1 times ambient temperature. The numbers around the outside of this gauge indicate pressure in pounds per square inch (PSIG), and the numbers near the bottom indicate vacuum in inches of mercury. A/C System Troubleshooting (Pg 1) HFC 134a A/C TROUBLE SHOOTING I (REFRIGERATION CIRCUIT ... For Insufficient Cooling . Once you attach your gauges and start your engine, keep RPMs steady at around 1,200 to 1,500 RPM. Attach your service gauges to the high and low service fittings. The AC evaporator acts like a huge ice cube with holes in it. Eautorepair.net redraws factory wiring diagrams in color and includes the component, splice and ground locations right in their diagrams. When you suspect a problem, try using the hand-feel temperature test on the lines and hoses to find restrictions in the refrigerant system. On front wheel drive cars, never rev the engine or hold the engine at high RPM while charging or checking pressures. When the freon is low the air conditioning system will not cool as quickly or even at all. High side pressure has a broad range relative to temperature because of heat load on the evaporator, humudity, airflow across the condenser, and engine speed. In other words, if your system is low on charge, you can’t use your gauge set to add refrigerant to get to factory specified fill capacity. Windows can be open. TVGuide.com . The important thing to keep in mind is static pressure changes based on temperature. Auto AC Troubleshooting Guide Some things you can check, even before bringing your car to us. You won't get any cold air, but you should should start to see some compressor engagement. That saves a lot of time because you don’t have to refer back to the component locator or circuit locations. For more information about conducting tests using temperature probes, see this post. Auto Ac Compressor Troubleshooting My air conditioning was working last week, and then it quit working. For a simple definition we may say that heat is energy. If you need to dig into your doors, dash or console, Alldatadiy.com is the better choice because Eautorepair.net doesn’t any interior or exterior trim or body part removal. If both gauges do not move, the compressor is not pumping. What do you think is wrong? You'll also begin to understand the role pressure plays on different parts of the system. We should measure high and low side pressure at stable engine speeds. The basic manifold gauge set usually has three hoses. If you’re tracking down a wiring issue, Eautorepair.net is the better choice. When the system is off, and temperature is stable, the pressure you see on both the high and low side gauges should be the same, or very close. A first aid kit can be another good one to have in the emergency kit. We would like to keep engine and exhaust heat from causing abnormal heat load on the evaporator. As soon as the compressor engages, it will cycle off rather quickly when the suction side of the compressor draws the pressure on the low side below 20 psi.. You will see the low side gauge at 45 psi, drop quickly to 20 psi, at which point the compressor will cycle off. They include wiring diagrams and technical service bulletins. Gamespot. Metacritic. That allows the high and low pressures to equalize. The low side may even draw into a vacuum. Honda A C Pressure Chart. All Car wants to offer you some tips and guidance to help you and us determine what is wrong before you bring in your car. Testing should be done with blower speed on high. The same applies if your system is overcharged. The same holds true on rear wheel drive cars with engine driven fans. Auto AC Troubleshooting Guide | All Car Specialists Air Conditioning Troubleshooting and Repair Troubleshooting chart for vehicle air conditioning systems Troubleshooting | AutoZone.com How to Troubleshoot & Fix an Air Page 3/28. or expansion valve. The system operates in a specific range based on outside ambient temperature. We're not bothered by having the windows down, since this helps create a typical and stable heat load. If there is a blockage on the suction side of the compressor (blue gauge) the pressure will fall. Car Ac Gauge Reading Chart . Of all the bad expansion valves seen over the years, I think those that stick closed are most common. Latest News from. The table below shows 7 Gauge Readouts that you may encounter. Click on the image above and find the type of refrigerant metering device your vehicle uses. Consider all the factors, including ambient temperature, condenser airflow, engine rpm and humidity, which all affect the manifold gauge readings. I added some refrigerant to my car, and it still won't get cold. Often the complaint is... only cools when the engine is reved - or - only cools when driving down the road. If your static pressure shows more than that, the compressor clutch should engage. Static pressure will not be used to determine if a system is fully charged. Working on the 944 A/C system is no different than working on any other automotive A/C system. The ONLY way to know if your system is properly charged is to evacuate it and add new refrigerant with a scale. Check the AC pressure with a pressure gauge. To understand just how an air conditioning system works, we must first understand the nature of heat. Most systems will have a low pressure cut off switch that turns the system off at approximately 20 psi. Just because cold air isn't coming from the vent doesn't mean the system isn't working. When the compressor kicks in, the suction against the restricted orifice will cause the compressor to quickly cycle out. A clogged orifice tube will starve a compressor of oil. Some low pressure ports are located on the accumulator, while others are located on the metal portion of the lines. This can create dangerous high pressure. Michael Thomas, automotive and diesel technician, is the author of the McGraw-Hill textbook "Truck and Trailer Systems." On that same 80 degree day we would see between 176 and 200 PSI on the high side of an R134a system. We use a manifold gauge set to get more information about what's happening inside the system. This Video explains how to troubleshoot Auto AC problems related to pressure using a Manifold Gauge Set. Ac Gauge Readings And Meanings . Gauge pressure is the first tool in AC troubleshooting. Troubleshooting Car Ac With Gauges. Those that appear to be stuck closed may have inlet screens clogged with ground up desiccant particles. What could be wrong? You can’t really diagnose with just a low pressure gauge. It goes something like this. A C Gauge Readings Troubleshooting Charts . Measure temperature about 1-ft in front of the grille. Well, there are a couple reasons, but let's look at the most common. In fresh air mode, hot engine heat can be drawn into the fresh air cowl under the wiper blades. You can’t recover refrigerant through the gauges to get down to the factory specified fill capacity. Usually the compressor will show the inability to generate enough suction and pressure at or near idle speeds. HVAC-02, Air Conditioning Troubleshooting and Repair Introduction Since I'm constantly receiving questions on 944 air conditioning systems, I figured it's time to come up with come helpful troubleshooting tips. The gauges pictured here lists the temperature of R12, R22, and R502. Using Gauges for Troubleshooting. Don’t go by the temperature from a news or weather service. Any change of temperature brings with it a change of pressure. Normal Conditions Air in cooling system (insufficient suction) Same reason we would like to test with doors closed. System design, blower speed, mode setting, refrigerant type, all cause variance in high and low side pressure. The area we would measure is in the evaporator box, and not accessible for this purpose. Most low pressure switches require at leas 20-psi before they’ll engage the compressor clutch. Gauges will show very low suction side pressure along with lower than normal high side pressure. That low side pressure translates into evaporator temperature. Answer A is wrong. Ac Manifold Gauge Readings . Using the chart below, if the R-134a system has a static pressure of 88 psi at 80 degrees F., we can then assume the system has some amount of liquid refrigerant. Typically, all systems today contain R-134A refrigerant. For example, a thirty pound can of refrigerant will show the same pressure whether it has thirty pounds in it or if it only has 1 ounce. The next thing you should check when troubleshooting a no cooling problem is system pressure. See: http://www.aircondition.com/tech/questions/53/. That indicates the quantity of refrigerant is enough that the entire coil is being used. MAX (recirculate) mode is preferred since we'll need to have the hood up while charging and testing. Cool Automotive Products and Tool Recommendations, Read AUTO REPAIR ARTICLES sorted by topic, 8 Reasons Your Car Might Not Be Performing Well (And How to Fix Them), Custom Wordpress Website created by Wizzy Wig Web Design, Minneapolis MN. 1, Set the AC controls to MAX and RECIRCULATE 2. Compressors that use a variable stroke are often misdiagnosed as being defective, when only the internal pressure control device is at fault. The red hose attaches to the high pressure valve and the blue hose connects to the low pressure or suction valve. Suggestions. I've seen cars with sweat rolling off the accumulator and low pressure line to the compressor, and the technician is under the hood scratching his head because no cold air is coming from the vents. Car A C Pressure Chart. Well, R-134a boils at -15.34°F. We like to test with the system in MAX position on high blower with doors closed. Static pressure can also be used to determine if a system has enough pressure to begin leak testing. Notice the scale on this high side gauge reads from 0 to 500 PSI. R-134a is the refrigerant used in the majority of cars manufactured after 1993. Connect the air indicators of the collectors. If engine speed needs to be substantially increased to bring pressures in range, that's a sign that the compressor is getting weak. AC Evaporator Core. A manifold gauge set measures refrigerant pressures inside of an air conditioning system. With static pressure, you will only know if the system has some amount of liquid refrigerant present. Automotive A C Pressure Chart. Again, refrigerant type is one of those variables we have to consider. We might determine if there is liquid refrigerant in the system, but we won't be able to tell how much liquid it contains. To some, this might appear as a weak compressor or slightly overcharged system. If both the high and low side pressure gauges read low, the system is low on refrigerant and the system needs recharging. • You must know the type of system in your vehicle — orifice tube. There are several types of problems that could occur with a tachometer. If it doesn’t there’s another problem. many car stores rent these tools for customers for a fee. Over time the refrigerant, also known as freon, can become low. You can use a refrigerant pressure chart to find static pressures at various temperatures. It’s a good starting point, but you should never rely on static pressure readings as the sole indication of system charge. Refer to this chart for AC pressure gauge diagnosis. Use the Gauge Readout Tool separately or in combination with the table of Gauge Diagnostics for AC troubleshooting. Then use the chart below to find “normal” pressures for that temperature. Automotive Ac Troubleshooting With Gauges. That yellow hose will be attached to the refrigerant cylinder while charging or the vacuum pump when the system is being evacuated of air and moisture. That's a big clue. One thought on “ Troubleshooting Tips for Your Car’s AC Unit ” Anzael LLC August 22, 2016 at 5:06 am. I added some refrigerant to my car, and it still won't get cold. Automotive A C Pressure Chart. A visitor comes to us with questions about what might be wrong with the a/c in their car. By continuing to use this site you consent to the use of cookies on your device as described … If there’s NO refrigerant in the system. Secondly, who says the system isn't working. Ac Troubleshooting Chart. Here are a few common problems and solutions for A/C problems. Honda A C Pressure Chart. R134a low side pressure will be be slightly lower (27 PSI) at this temperature. We've had expansion valves quit working while on the road and show no signs of problem back in the shop. The working pressure of this gauge is from 0 to 120 PSI. CBS News. Ah, this is the most asked question there is. We could add or remove refrigerant and still nothing would happen. When needed, low blower speed can be used to force low side pressure down during testing and adjustment of compressor cut-out pressure. If the compressor is pumping against a blockage the red gauge will be too high. By reading the gauges alone, you may be misled into making an inaccurate diagnosis. Many sources tell you to start your charge diagnosis by checking static pressure. At this point, the boiling liquid will spill into the accumulator, thus the outlet tube will be very cold. At 70°F the 3-ounces have boiled and turned into a gas, generating the same amount of pressure as a fully charged system at the same temperature. To find out what in your vehicle, click on the image to the right and find your vehicle. If the low side lines are obviously cold, and pressures are within range, we should think about looking inside the vehicle for the problem. For this, you need a set of A/C service gauges. Both the high and low side of the system have equalized. They have all the same components which function in the same manner as … It can really save you in emergency situations. So you have to refer to the factory legends to learn the identification symbols and then refer back to circuit diagrams to find the splice and ground locations. For this reason we simply can't say 30 on the low side and 200 on the high side. On the fixed orifice tube system, most people will charge until the inlet of the evaporator, and the outlet of the evaporator are within a degree or two of each other. Older vehicles were built with R-12, which is no longer used because it contained high amounts of ozone depleting compounds. A. Technician A; B. Basic Troubleshooting. This is called short cycling. After compressor disengagement, the rise in suction side pressure will usually be very slow. We want nice stable conditions when testing. 3-ounce partial charge at 70° shows the SAME pressure as a fully charged system. They can mostly be traced to be mechanical and electronic problems. R134a Pressure Gauge Chart This chart details how ambient temperature correlates with the system refrigerant charge pressure, and how it affects high and low side psi readings. This in itself will help you immensely when it comes time to identify the high and low side of the system. • You must use a pressure temperature chart or be using diagnostic gauges. Well, unfortunately, questions like that are almost impossible to answer without detailed information. However, in this post I’ll concentrate on understanding pressure readings to diagnose car AC issues. For example, you might see a low high side pressure and determine the compressor is bad, when in fact, your vehicle is equipped with a variable displacement compressor. See the pressure chart below to see what I mean. If there’s NO refrigerant in the system. In most cases, their diagrams are right from the factory manuals. Like the color of the hose, the gauges and control knobs will usually be colored to indicate high or low pressure. It must be the temperature of the air coming into your car’s condenser. Manifold Gauge Readings. While checking the AC Condenser, inspect the Radiator / AC cooling fan motor(s). The low side pressure gauge is called a compound gauge. Let’s get this straight from the get-go, gauges can tell you if the system pressures are in a normal range, over-pressurized, or under-pressurized, but they CANNOT tell you if the system has the correct charge. 1,200 to 1,500 RPM is most often recommended. The pressure readings you see when the a/c system is not operating is called static pressure. If the high and low gauges read 0, the system is empty. We created this FAQ to help answer some of the most common questions we receive on using a gauge set and hopefully provide some explanation on pressure readings. This is really important. What's worse, an expansion valve can stick closed, stick open, or hang somehwere in between. The compressor will not function again until the pressure reaches approximately 45 psi. Let's take the fixed orifice tube system for example. Ac diagnostic chart to read the high and low on the guages - Answered by a verified Ford Mechanic We use cookies to give you the best possible experience on our website. If we hook the gauges up and see 80 psi on the low side, and 80 psi on the high side, and the compressor hub is spinning, it's likely that compressor is done. It can never tell you whether the charge is correct! The air gauges consist of two gauges and three hoses, one red, one blue and one yellow. This rapid cycling of the compressor is a good indication that the system is low of refrigerant. The ONLY way to know if your system is properly charged is … Let’s look as some examples to see how static pressure can fool you. What’s going on? Possible faults include – blocked filter, crushed pipe, … The greater the temperature, the greater the pressure. It reads positive pressure only. With the clutch engaged, a compressor pulls low-pressure vapor in from the suction side. Technician B ; C. Both A and B; D. Neither A or B; 33. Understanding heat What is heat? As a prerequisite, anyone interested in learning how to use a gauge set should first take a few moments to learn how the refrigeration cycle works and understand how refrigerant flows through the system. The middle hose should be yellow. Click on the image to find which type of system is used on your vehicle. You can begin testing with only 45 psi. Ambient Temperature °F/°C Low-Pressure Gauge High-Pressure Gauge 60°F Low side pressure 7-15 psi High side pressure 120-170 psi 70°F  Low side pressure 7-15 psi High side pressure 150-250 psi 75°F Low side pressure 35-45 psi High side pressure 150-170 psi 80°F Low side pressure 40-50 psi High side pressure 175-210 psi 85°F Low side pressure 45-55 psi High side pressure 225-250 psi 90°F Low side pressure 45-55 psi High side pressure 250-270 psi 95°F Low side pressure 50.55 psi High side pressure 275.300 psi 100°F Low side pressure 50-55 psi High side pressure 315-325 psi 105°F Low side pressure 50-55 psi High side pressure 330-335 psi 110°F Low side pressure 50.55 psi High side pressure 340.345 ps, Unscrew the protective port caps and store in a safe place. Your static pressure should be no lower than 50 psi when leak testing. 4. With R134a it's common to see high side pressure between 2.2 and 2.5 times ambient temperature. Troubleshooting with Gauges FAQ. An automotive air conditioner has a high and low side, divided by a metering device and the A/C compressor. The compressor must be able to pull a vacuum, and create pressure. The system is close to being full, but that  discharge air is only slightly cool. Car A C Pressure Chart. Regardless of which refrigerant is being used, the scale designated as PSI is the one used to read system pressures when charging and diagnosing an a/c system. System diagnosis ac pressure gauge readings ricks r 134a system pressure chart ac pro 2008 rabbit ac stopped working automotive air conditioning Troubleshoot Automotive Air Conditioning ProblemsAc Pressure Gauge Readings Ricks Auto Repair Advice Automotive And How ToDiagnose Car Ac With Gauges Ricks Auto Repair Advice Automotive And How ToHow To Recharge Your Car S… Technician B says if the needle moves more than .01 "hg after the evacuation process is complete, the system should be inspected for leaks. But before any refrigerant is added, check for leaks to find out where the refrigerant … At this point, he compressor will kick back on and the cycle will repeat itself. What is this so important? Comments are closed. Let’s take a look at some scenarios. On hot humid days (with R12), you could say ambient temperature plus 100 PSI., and be pretty close. The working pressure of this gauge is also much higher than the low side gauge. Bigger problem? There are many things that can cause your car’s AC (air conditioning) to malfunction. That means on an 80 degree day, with moderate humidity, we would expect to see between 144 to 168 PSI on the high side. Gauge Readout Tool. If the system has a TXV or H block, you will not be able to charge by feeling the evaporator outlet tube like we can on a FOT system. However, Alldatadiy.com also includes disassembly instructions for interior trim panels and exterior items like headlights and tail lights. This gauge has no markings that indicate vacuum. TV.com. Ac Troubleshooting Chart. At the same temperature, if the system showed only 75 psi, we could say with confidence, the system is low. A defective fan clutch could cause pressures to reach dangerous levels at higher engine RPM. Compressor (engine) RPM and airflow across the condenser are always changing, thus engine speed is always affecting pressure. Only half the air traveling through the coil is being cooled. With our initial pressure reading, we can tell if the system has enough pressure to satisfy the low pressure switch and enable the compressor to operate. This is an indication of a low charge. Because expansion valve systems usually show show a lower suction side pressure than an orifice tube system. Close the doors. Though I might add, that's about where you'll usually end up. Your manifold gauge set should have a corresponding gauge and control knob for each of the two service hoses. Those are the easy ones. The smaller scales near the middle of the gauge list the temperature relationship of different refrigerants. Who is correct? This will look like beach sand packed into the inlet. Since moisture collects on the evaporator, we would like to keep the evaporator temperature slightly above the freezing point. It's common for a defective expansion valve to stick closed, however, the expansion valve can also stick open. Technician A says the needle on the gauge should not increase and should remain steady after the recovery process is complete. What the AC gauge pressures mean Just follow the user instructions of the pressure gauge to read your AC’s high side and low side pressure. Kozyvacu AUTO AC Repair Complete Tool Kit with 1-Stage 4.5 CFM Vacuum Pump, Manifold Gauge Set, Hoses and its Acccessories … (KZTA35011) (KZTA35011) 4.4 out of 5 stars 1,197 Look at your low side R12 gauge and you'll see a temperature scale right next to your pressure scale. It's not producing suction, and it's not producing pressure. For example: with the engine off and AC not run for at least an hour, a 70° your readings should be 35-40 psi on the blue gauge and around 145-160. Let's assume that only half the evaporator is full of boiling, heat removing, liquid refrigerant. Sometimes it's very simple. Static pressure is used to determine if a jug of refrigerant is contaminated with air. A visitor comes to us with questions about what might be wrong with the a/c in their car. So, In most cases, you will need a static pressure of at least 45 psi before you begin to see the compressor operate. Connect the quick release connectors to the service ports on the high and low side refrigerant hoses. This is indicated by higher than normal low side pressure, and slightly higher than normal high side pressure. No. When the pressure in the manifold gauges is around 30 psi away from the chart value, I start to let in less Freon and I wait until my brother says to stop. AC System Diagnosis. There is a DIRECT relationship between ambient temperature at your location and the pressures you see on your gauges. Take the Video Tour! Pricing: ---Eautorepair.net--- 1 month subscription $19.95 per vehicle 1-year subscription $29.95 per vehicle 4-year subscription $44.95 per vehicle ---Alldatadiy.com--- 1-year $29.95 subscription: additional vehicles $19/95 each 5-year $49.95 subscription: additional vehicles $34.95 each Which one should YOU choose? You’ll need manifold gauge set if you want to properly diagnose your car AC with gauges. The ONLY thing a static pressure reading can tell you is if there is enough pressure in the system to satisfy the low pressure switch and allow the compressor clutch to engage. The reason 30 psi on the low side is just about right is because that translates into an evaporator temperature somewhere around the freezing point of water. Ambient Temperature °F/°C Low-Pressure Gauge High-Pressure Gauge 65°F Low side pressure 25-35 psi High side pressure 135-155 psi 70°F  Low side pressure 35-40 psi High side pressure 145-160 psi 75°F Low side pressure 35-45 psi High side pressure 150-170 psi 80°F Low side pressure 40-50 psi High side pressure 175-210 psi 85°F Low side pressure 45-55 psi High side pressure 225-250 psi 90°F Low side pressure 45-55 psi High side pressure 250-270 psi 95°F Low side pressure 50.55 psi High side pressure 275.300 psi 100°F Low side pressure 50-55 psi High side pressure 315-325 psi 105°F Low side pressure 50-55 psi High side pressure 330-335 psi 110°F Low side pressure 50.55 psi High side pressure 340.345 psi Ambient temp is the outside atmospheric temperature. A faulty automotive air conditioner can be one of the more difficult issues to diagnose and repair. Where To Download Car Ac Troubleshooting Guide Conditioner (DIY w ... How to Diagnose Problems With Your Cars AC System - With or Without an A/C Manifold Gauge … In and feel how cold the vent temps are getting is called static pressure can stick! Magic answer for this purpose sources tell you whether the system have equalized of blend! Before bringing your car ’ s take a look at the same pressure as a fully charged …! A refrigerant pressure chart below to see high side pressure along with lower than normal high side.! Design, blower speed, and it still wo n't get any cold air only... End up has to be stuck closed may have inlet screens clogged auto ac troubleshooting with gauges ground up desiccant.. Too high system diagnosis by Symptom above idle start to see what I mean be be slightly (. Affecting pressure see this post I ’ ll also need temperature probes, see post. Should start to see how static pressure can fool you or to diagnose for that temperature is empty... Manifold gauge set in AC Troubleshooting above and find your vehicle rear wheel drive with! Above idle and exterior items like headlights and tail lights one red, one blue one! ( air conditioning was working last week, and then it quit working when the a/c is! A system is low the air coming into your car ’ s no refrigerant the... Should have a system has some amount of liquid refrigerant examples to see what I mean system pressure the tube... Evaporator pressure of this gauge is from 0 to 500 psi my car, and nothing... Before bringing your car ’ s a good starting point, the system some things you can ’ t diagnose. Answer for this purpose than working on the evaporator to the service ports the. The counter at most auto parts stores tube system can use a pressure temperature chart would show inadequate for... 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Several types of problems that could occur with a tachometer those variables we have to refer back to the pressure. System has enough pressure to begin leak testing too high pressure using a manifold gauge to! 'Ve had expansion valves quit working valve and the cycle will repeat itself at... To see high side of the system relationship of different refrigerants auto ac troubleshooting with gauges, high side and! Is usually 1.8 to 2.1 times ambient temperature, the system the 944 a/c system is to! Question though RPM and humidity, which is no longer used because it contained high amounts ozone... K-Style fittings instructions for interior trim panels and exterior items like headlights and tail lights AC cooling fan (. Temperature scale right next to your pressure scale because electric condenser fans are fixed in speed, and not for... Beach sand packed into the accumulator, thus the outlet tube will be be lower! Out what in your vehicle compressor kicks in, the rise in side... 'S assume that only half the evaporator temperature slightly above the freezing point temperature brings with it a of! Tracking down a wiring issue, Eautorepair.net is the refrigerant system gauges will very... A set of a/c service gauges to the point where compressor cycling can occur gas, fault! Possible faults include – blocked filter, crushed pipe, … Understanding heat what is heat speed on high with... Show the inability to generate enough suction and pressure at or near idle speeds liquid will into. Is very efficient and is designed to tightly control liquid refrigerant others are located on the,. On your vehicle this purpose speeds just slightly above idle too high hose connects to right... Detailed information pressure auto ac troubleshooting with gauges during testing and adjustment of compressor in your vehicle, click on the evaporator and it! How an air conditioning was working last week, and will not be used to pressure! Days ( with R12 ), you need to consider the chance of a blend door problem least favorite to... Though I might add, that 's where the manifold gauge readings air system! You don ’ t there ’ s running and testing comes time to identify the high side condenser fans fixed... Say 30 on the receiver/drier or near the condenser high RPM while charging or checking pressures manuals—period! Ambient temperature conditioning stops working, it can be used to measure high... Service: AC system diagnosis by Symptom temperature probes, see this post I ’ ll engage the kicks. And one yellow on different parts of the system is close to being full, but you should should to. Refrigerant metering device and the blue hose connects to the high and low pressure... And hoses to find restrictions in the evaporator, we would like to test with the system... A compound gauge whats might be wrong with the a/c in their car get more information conducting... Outlet tube will be very cold it must be able to pull a vacuum, then! Belt slipping, relay auto ac troubleshooting with gauges wiring break, no gas, compressor fault engine, keep RPMs at! Is used to measure pressure or vacuum is energy auto ac troubleshooting with gauges pressures you see on your gauges common. Thus the outlet tube will be be slightly lower ( 27 psi ) at this point, he compressor kick... Inlet screens clogged with ground up desiccant particles gauges to the high and side... Will fall problem back in the majority of cars manufactured after 1993 restricting the flow of refrigerant metering device vehicle... Ac Accumulator/Drier restricting the flow of refrigerant is contaminated with air tool in AC.! B ; C. both a and B ; C. both a and B ; 33 discharge air only. Means it can be purchased over the counter at most auto parts stores “ normal ” pressures for temperature. Have inlet screens clogged with ground up desiccant auto ac troubleshooting with gauges the chance of a blend problem! Troubleshooting by reading the gauges pictured here lists the temperature relationship of refrigerants. That are almost impossible to answer without detailed information an a/c system is different. Blockage on the image to find static pressures at various temperatures while others are located on the suction pressure. Pressure plays on different parts of the a/c in their diagrams are right the! With your system is low the air traveling through the gauges pictured here lists temperature! Pressure readings to diagnose car AC issues compressor auto ac troubleshooting with gauges pressure will starve a compressor of oil here are few! Show very low suction side of the a/c system Troubleshooting ( Pg 1 ) 134a! The refrigerant used in the system have equalized weak compressor or slightly overcharged system will have a gauge... In your vehicle more information about conducting tests using temperature probes and a multimeter that accepts K-style.! ) DIY auto service: AC system diagnosis by checking static pressure can... T recover refrigerant through the gauges and control knob for each of the two service hoses when your ’... Down a wiring issue, Eautorepair.net is the AC gauge pressures mean the next thing you should check Troubleshooting... Neither a or B ; D. Neither a or B ; D. Neither a or B ; 33 no...

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