First make sure that the vehicle's battery is fully charged. Just make sure it can test amperage, has an auto ranging mode, and is at least a known brand. B - Connect the meter to the battery on the volts DC scale, if the meter has min/max function use it (this will capture the high voltage peak, and low crest. Alternator, or related, faults that can cause the above symptoms are: Reduced output from winding or diode faults, caused by heat and vibration or the inclusion of moisture into the circuitry. Why is it not charging? Jump to Latest Follow 1 - 10 of 10 Posts. This is the only test needed to tell whether the regulator is good or not. I am using a V-max stator as an example, check your bikes. Faulty voltage regulators (where applicable) causing alternator output to increase with increasing engine speed. I think we'd all agree that's much too soon for an alternator to die. A good alternator should measure less than. Step 2: Test the resistance. A battery and charging system test (AVR test) can cost from $30 to $50. Viewing the alternator output with an oscillo-scope is the preferred technique for diagnosing You can quickly test for ripple with a Digital Multimeter (DMM) set on AC volts. Your battery may be failing but for you to be sure you need to know how to test a car battery. Okay but the problem is to "test" batteries when the tester is not handy This is a dinky solution as you do not need an "expensive" tester for a lay person. In the photos of this article we used a more expensive Fluke multimeter. Checking the Car Battery When the Engine of the Car is Running. I want to test my generator to see how many amps it's putting out at idle. In this article, we'll cover how to. A multimeter’s Diode Test mode produces a small voltage between test leads. The best thing to do is either get a meter or take the alternator off and take it to an auto parts store and have it checked. AC tests are made for AC volts while tests for DC charging output are made in DC amps. The orange wire is B+ and the black wire is B-. 04 volts less. Check also that the dynamo actually turns when the engine is running, and that the drive belt is adjusted to its correct tension, and is not slipping (See Checking, adjusting and refitting drive belts). One or both will be used to check the health of all Briggs & Stratton alternator systems. The battery of my Camry 2009 XLE 3. So we take the ohmmeter and place it across the leads of the diode. There are a few things to inspect, such as: a broken terminal, bulge or bump in the case, crack or rupture of the case, excessive leaking, and discoloration. The easiest way to test an alternator is to check the output voltage, and a lot of instrument clusters even include built-in voltmeters. If the alternator was bad, then driving to autozone and then back could be enough to drain the battery - particularly since it sat for a few days after that. How to check the alternator with multimeter. If you lose a single diode, the alternator would behave in just this manor. So, if you’re looking to buy an alternator tester, we have some good recommendation for you. The purpose of the rectifier on an outboard motor is to force the current to flow in one direction only, using diodes, which are like one-way electrical valves. The one marked B+ next to the 8mm stud with the nut on it gets wired directly to the battery with a nice decent size cable. One method to test the alternator is to perform a charging system test. at 2,000 RPM 32 to 40 AC volts, 3,000 RPM 48 to 60 AC volts. Disconnecting the battery while the engine is running isn't a valid test for alternator function and may damage sensitive electronic parts. Listen for a rattling noise in the area of your serpentine belt. Connect the meter leads to the battery terminals and look for 13. Set your multimeter to DC to test the. This should be one of the first things you might want to do if you suspect you have an electrical problem in a car. OK, the test is divided into three parts: PART 1- Testing the alternator voltage output with the multimeter in VOLTS DC mode. If it is fully charged it will be about 14 volts. The starter on your car's health is directly related to how many amps it pulls from the battery. Testing Electrical Systems with a Digital Multimeter Perhaps the most important tool you'll use in troubleshooting auto electrical systems is the multimeter. As you know, two types of multimeters are. Electrosport Industries) as a preventive maintenance action in preparation for a 2006 vacation trip. A good alternator should measure less than. The first check to see if your armature windings are shorted is the "180° Resistance" test. The alternator in the 1966 Ford Mustang must produce at least 12 volts of charge to satisfy the vehicle's electrical needs. Use a multimeter on a 20 volt setting to test the voltage of the alternator. However, it is not the only test available for you. I'd think the reading should rise once the motor is running and rise even more once its under full power. Additionally, inspect the wiring from the alternator to the battery for any signs of damage, loose wires, or misconnections. To that end, you can measure the actual output of an alternator under a simulated load, which allows you get an idea of what it is capable of putting out in real-world conditions. Instead, use a common voltmeter and the following test. The alternator must be running to test without disassembly. Bad battery or bad alternator, how to tell the difference (brief version) - Auto Information Series - Duration: 8:42. We suggest you calibrate using test equipment found at many stations or car. Most of the car alternator tester can test both the alternator and battery. You can also evaluate your alternator without ever using a voltmeter. I'm no EE, but here is how I understand it: Some multimeters have a battery test function on them. Alternator output on green scale. You can check its voltage with a multimeter. Inspect the fan belt which runs the alternator. Most uninformed know as much from electricity as a cat know of saffron and it scares them. I called my usual mechanic and he said it could still test good and have an internal diode burned out. Here's how you can test your car alternator for power, so that doesn't happen to you. Most service stations can test an alternator, but they will charge you for the labor. Electrex a. Test your NiCad battery pack to find out the voltage and mAh using a multimeter. Multimeter Basics. Here are a few Simple Tests to determine if these parts are OK, and all that is required is a Digital Voltmeter and probably Two people. This ON CAR TEST doesn't require any tools, such as a multimeter or anything else. If results are now satisfactory (0. It's usually caused by a ground connection that is less than ideal. First take volt reading without bike running. Of course, at no current flow, the needle should read zero. If you lose a single diode, the alternator would behave in just this manor. DIY how to test a BMW E39 battery & alternator (discussion) Compliments of bluebee @ bimmerfest. Alternator problems manifest themselves in various ways, depending upon the particular failure. Remove the fan belt. Any reading less indicates a problem with the rectifier, alternator, or regulator, if so equipped. It's a fast test and more importantly an effective test to find out if the alternator is in fact bad. using the AC function when the alternator is putting out AC 16+ volts and an alternator should put out 13. It's important to note that once an alternator goes bad the electrical devices will attempt to draw power from the battery, which in turn could cause the battery to die more quickly. If it's more than seven years old and you'll be traveling alone without easy access to a jump, replace it. Does your car not start, do you have dim headlights or interior lights, does the starter sound weak when start the How to T est a Car Battery with. How to test an Alternator How to test an alternator. If you do get a reading when doing this it is indicating that you have a shorted stator winding, which means it is touching ground and is shorting out your winding. And whether you're driving a Ford, a Chrysler or a Dodge or a Plymouth, a Nissan, a Mitsubishi, a Volkswagen or whatever, this test will work. Use caution, however, as a dying battery can only receive a charge for so long and may go completely dead at a later point despite the best efforts of the alternator. You could test this with a multimeter. Also indicated as 300mA (mA x 1000 = A). The battery of my Camry 2009 XLE 3. If the results of your test fall somewhere under the 13 to 14-volt range, then you're still okay. I have tried several times to attach the multimeter to the alternator but I keep getting the reading of 12. A digital multimeter is an extremely useful tool to have around the house, here are some tutorials covering other things you can do with one: Here we explain how to locate a buried cable fault with a digital multimeter. Repeat LOAD TEST. So, if you’re looking to buy an alternator tester, we have some good recommendation for you. Printed in U. The reading of each combination should be the same (test leads 1-2, 2-3, and 3-1). When you have one, attach the multimeter's clamps to your vehicle's battery. , If Ordered Now, Ships in 7 Business Days 100% guarantee. A multimeter is an electronics testing device that, um, tests multiple things, including resistance, voltage, and current. ALTERNATOR OUTPUT TEST The alternator output test checks the ability of the alternator to deliver its rated output of voltage and current. I do not know what you are hoping to achieve To carry out a meaningful test you need a voltmeter to measure the output volts an ammeter to measure the output current and a means of applying a appropriate load to the alternator. If the old alternator passes the tests, the problem is obviously not the alternator, and you've missed something. Here are a few Simple Tests to determine if these parts are OK, and all that is required is a Digital Voltmeter and probably Two people. see if the amount of current is to high. How to test a car battery without a multimeter. upon return, the dealership informed me that the alternator was good so I reassembled the unit. The tach pointer may not rest at zero with engine off. I want to test my generator to see how many amps it's putting out at idle. I have tried several times to attach the multimeter to the alternator but I keep getting the reading of 12. Hmmm? Battery is good, Alternator is good, but will not charge. Posts Tagged: test alternator without meter How to test an Alternator April 23, 2010. As you know, two types of multimeters are. First test the AC voltage from pin to pin at the alternator plug just like Ender did. Here’s how. I was looking for a cheap and easy method to quickly test battery charge levels and potential alternator issues. The Battery Life Saver™ electronic device will not help a battery or batteries that have an open or shorted cell. If the battery warning light has been on while driving the car you will need to test the alternator first. Couldn't get to the spot on the alternator, drats. Take the negative lead of the multimeter and put it on the negative post of the battery. If you lose a single diode, the alternator would behave in just this manor. Bring the vehicle to a fast idle of around 2000 rpm and turn on accessories like the headlights, A/C blower motor, etc. We aim to cater for a wider range of tastes here from Hot Rods & Street Rods all the way through to Bikes and Trucks. Local Dallas shop installed our an alternator on a 2001 Chrysler PT Cruiser for his customer. OK, the test is divided into three parts: PART 1- Testing the alternator voltage output with the multimeter in VOLTS DC mode. 2015 Dodge Dart 2. My battery (age unknown) has died and I want to determine if the alternator or some other component of the charging system is at fault other tha …. Conclusion. Consult the manual on the correct testing procedures when using a multimeter to prevent accidental short circuits. 6 Ways to Check a Capacitor by using DMM & AMM (AVO). At this point, check to make sure the alternator pulley / belt is spinning properly without slipping. I'm figuring out the simpest way to turn it into a wind-driven generator (without replacing the all-electromagnetic rotor with a permanent magnetic rotor). Do not disconnect the positive, more potential for unwanted sparks. This is because the battery might not be the problem if it is not receiving a proper charge from the alternator. Then test after an overnight rest. Learning how to diagnose a "no charging scenario" is where it tends to get a little trickier. Ideally it should be putting out 13. Instead, use a common voltmeter and the following test. Use a multimeter to find out how well these different liquids conduct electricity. Before starting to troubleshoot an electrical problem, make sure you get yourself a good multimeter. I have a full diagram of the 1989 Mustang here 1989 Ford Mustang Wiring Schematic. I think you can do a similar test without an inverter by starting the motor and then turning on every dc appliance you have - lights, fans, electronics, etc. The multimeter should read under 1 Ohm for all three (make sure to take into account the resistance between the leads). This should be one of the first things you might want to do if you suspect you have an electrical problem in a car. The starter on your car's health is directly related to how many amps it pulls from the battery. If it's in the range, it's good. Will check tommorow with 2nd person multimeter on battery test (after manually recharging battery) to confirm alternator deadness. as they say, you can test alternator voltage at the battery terminals. meter movement. If the lights dim, the alternator works. Many auto parts stores will test alternators, starters and batteries for free, though you will have to remove the alternator to have it tested at an auto parts store. To that end, you can measure the actual output of an alternator under a simulated load, which allows you get an idea of what it is capable of putting out in real-world conditions. To test your vehicle’s voltage regulator, you’ll need a multimeter, which reads the voltage running through your battery. The multimeter. This ON CAR TEST doesn't require any tools, such as a multimeter or anything else. For example: high setting on your multimeter may be 10 Amp. Place the RED test lead onto one side of the diode being tested and the BLACK test lead onto the other side. We’ll cover the symptoms of when an alternator goes bad, and how to diagnose a bad one (which is really pretty easy). A fresh battery and a malfunctioning alternator, however, will quickly leave you stranded again. worn alternator can test ok on voltage, but will not keep battery charged, if you're using the power elsewhere. This test will show if the alternator is workingwhen you take battery cable off with the engine running, if the engine dies the alt. Hmmm? Battery is good, Alternator is good, but will not charge. ALTERNATOR OUTPUT TEST The alternator output test checks the ability of the alternator to deliver its rated output of voltage and current. 4 volts but unless you have a fancy alternator regulator that is about the highest you should see. How to test alternator without multimeter - Coolcircuit. Check out this video to see how it's done! You're driving down the road and all of a sudden SNAP—your alternator belt just snapped. Your equipment needs for this are very simple. A fresh battery and a malfunctioning alternator, however, will quickly leave you stranded again. If the old alternator passes the tests, the problem is obviously not the alternator, and you’ve missed something. However, it is not the only test available for you. the alternator's stator coil had failed. Small screws work, with a clip lead. PART 3- Verifying that the alternator fuse in the fuse-box is not blown (if equipped). I measured the battery voltage when the car was off and it re. You need a "floating ball" battery tester to check the specific gravity of your battery's fluid (assuming you do not have a sealed battery), and an inexpensive multimeter. 3 volts (engine running, lights and accessories off). Measuring forward voltage of a diode without"diode check" meter function: (a) Schematic diagram. How to test a starter motor. First inspect the alternator, for loose wires, connections, etc. Please read the entire procedure before starting. Using a Multimeter to Test Your Alternator. if not then the alternator is dead or dying, if so then. An alternator should put out a. 2 so if the voltage is 6 volts, the pack contains six cells. Take it to a professional for a final diagnosis. You can check the amount of A/C voltage leaving the alternator by putting your multimeter leads on the battery (Positive lead on +, and Negative lead on -), with you multimeter set on A/C voltage you should read no greater than. If significantly more AC voltage is present, alternator should be replaced. If you want to gamble with 40 bucks. These modes are diode mode and ohmmeter mode. Connect a wire from the battery + terminal to D+ on the generator. Learning how to troubleshoot a motorcycle's charging system can be one of the more difficult tasks to fully understand. DC Volt/20V Setting: First and foremost, ensure you have a working multimeter that has a good battery in it. Not sure if your alternator is in tip top shape? It's hard to tell whether or not an alternator works if you don't know what to look for. The reading of each combination should be the same (test leads 1-2, 2-3, and 3-1). Here's how we can check a charging system with a few simple pieces of equipment. No multimeter needed. Testing Your Charging System. Unplug the connector to the alternator and hook your multimeter leads to the alternator (pin/socket selection does not matter) set the multimeter to AC volts, at an idle the multimeter should read 16 to 20 volts AC. Once connected to a terminal, an alternator should test between 12 and 13. Keep the digital multimeter (DMM) in diode checking mode by rotating the central knob to the place where the diode symbol is indicated. You should then fully charge the battery with a battery charger then test no less than 12 hours later. To that end, you can measure the actual output of an alternator under a simulated load, which allows you get an idea of what it is capable of putting out in real-world conditions. How to Test Alternator Without Multimeter? Did you know that you can use a voltmeter and other methods to test it? If you are one of the many who is wondering how to do it, then the information below will surely help you. Step 2: Test the resistance. When you have one, attach the multimeter's clamps to your vehicle's battery. I have a 1995 Ford Taurus Wagon GL with a 3. Of course, at no current flow, the needle should read zero. To that end, you can measure the actual output of an alternator under a simulated load, which allows you get an idea of what it is capable of putting out in real-world conditions. Take the negative lead of the multimeter and put it on the negative post of the battery. By continuing to use this site you consent to the use of cookies on your device as described in our cookie policy unless you have disabled them. If the engine cuts off, it is a sure sign that the alternator has died. The back of the alternator has several wires connected to it, unless it is a single wire system. Attach both leads of the meter to the coil-terminals with black to the negative terminal and red to the positive one. A good alternator should measure less than. Bench Test Alternator with Multimeter 2:19 How to test your vehicles alternator using a 9:06 HD How to Test an Alternator 11:33 HD How to Test an Alternator - Diagnose Charging 11:47 HD Alternator - How to test using a Voltmeter 0:49 HD How to test an alternator (without multimeter) 3:01 HD How to Test Alternator Voltage Output 2:35 HD Quick. so we had to run the engine with. Okay but the problem is to “test” batteries when the tester is not handy This is a dinky solution as you do not need an “expensive” tester for a lay person. If the alternator was bad, then driving to autozone and then back could be enough to drain the battery - particularly since it sat for a few days after that. Check out this video to see how it's done! You're driving down the road and all of a sudden SNAP—your alternator belt just snapped. In this article, we'll cover how to. It has a 20 feet cable that allows one to power up and ground any circuit from bumper to bumper without the need for jumper leads. I have tried several times to attach the multimeter to the alternator but I keep getting the reading of 12. Most uninformed know as much from electricity as a cat know of saffron and it scares them. You can quickly determine if the alternator and battery are functioning properly by performing simple tests. To check a 12 volt coil, set the multimeter to at least a 200 Ohms setting. DIY how to test a BMW E39 battery & alternator (discussion) Compliments of bluebee @ bimmerfest. The easiest way to test an alternator is to check the output voltage, and a lot of instrument clusters even include built-in voltmeters. Unplug the connector to the alternator and hook your multimeter leads to the alternator (pin/socket selection does not matter) set the multimeter to AC volts, at an idle the multimeter should read 16 to 20 volts AC. Then I bought and installed a brand. Visually inspect the battery. worn alternator can test ok on voltage, but will not keep battery charged, if you're using the power elsewhere. Why is my battery cable getting so hot? maintenance & nonperformance. Step #10 Start engine and test alternator. It should read approximately between 13. The battery holders in sizes AAA, AA, C, and D make this tester so much faster than a voltmeter. Try to buy one equipped with an amp clamp. If it's declining steadily with the engine running, you have a blown fuse or a faulty regulator or bad alternator. Normally, when we test for continuity, we are not so much concerned with the resistance, but the lack of it. I know you used to have to pull the alternator off before they tested it at AZ or Advance Auto Parts. Does your car not start, do you have dim headlights or interior lights, does the starter sound weak when start the engine, or does your car die sitting overnight?. How do you test an alternator while still mounted to the engine without using a meter? NEVER EVER disconnect a battery cable while the engine is running. Prepare the diode prior to testing for the most accurate result. Alternator harness for easy hook up of foreign and domestic alternator test leads. Check also that the dynamo actually turns when the engine is running, and that the drive belt is adjusted to its correct tension, and is not slipping (See Checking, adjusting and refitting drive belts). The alternator will charge the battery at around 14. There’s also another way to check the alternator manually. If you haven’t already, have your battery and alternator checked before you purchase or attempt to work on anything. You could test this with a multimeter. well here is the rest of the story, when I first got the car together a few months ago, The car drained the battery in the first day or 2, and it turned out being a loose alternator cable nut. If a multimeter with diode-check function isn't available, or you would like to measure a diode's forward voltage drop at some non-trivial current, the circuit of the figure below may be constructed using a battery, resistor, and voltmeter. Angle test leads. I do not know what you are hoping to achieve To carry out a meaningful test you need a voltmeter to measure the output volts an ammeter to measure the output current and a means of applying a appropriate load to the alternator. This is a common test performed at dealerships and auto repair shops. Solid state electronics don't react well to the voltage surge that results when the battery is disconnected while they are on-line. Dunno about the meter. If the battery is working properly and nothing is wrong with it, then it's the alternator that will more likely cause a problem. When you have one, attach the multimeter's clamps to your vehicle's battery. Should be around 12 volts. The battery also acts like a huge capacitor that smoothes out the power delivery from the alternator. Inspect the Power Belt and Wiring – The power belt should be up and running when the engine is on and the wiring between the alternator and the battery should not be loose, damaged, or corroded. Hence the 'multi'-'meter' (multiple measurement) name. But that doesn't rule out the alternator. I say expect around 14 to 14. A higher reading indicates damaged alternator diodes. Insert RED test lead (A, Figure 28) into the V ω receptacle in the meter. The plan is to mount it on my Super Dexta, but this would need some work as there's currently a dynamo which is starting to fail. OK, the test is divided into three parts: PART 1- Testing the alternator voltage output with the multimeter in VOLTS DC mode. Problems with the car battery can result into problems with ignition and many more devices dependent on the battery for power. The multimeter should read under 1 Ohm for all three (make sure to take into account the resistance between the leads). Imagine, if you had to travel to a remote area, only for the car battery to fail without the sign of a mechanic in the vicinity. I have a multi-meter that has an amp setting, but it says 10A max. Check & Test a Capacitor using Analog Multimeter Test & Check a Capacitor with a Digital Multimeter Checking Capacitor By Multimeter in the Capacitance Mode Check and test a capacitor by simple voltmeter Traditional Method to test & check a capacitor Find the capacitor value by measuring the value of Time Constant. Using a voltmeter is one of the most practical and most accurate ways you can determine the condition of your car's alternator. If you don't have a multimeter to tell you the voltage of your battery, you can do a test of your electrical system by starting the car and turning on the headlights. haha, those may work but the only sure fire way is to start the car, get a multimeter on the battery or alternator (either works) and the voltage at idle if working should be between 12. Local Dallas shop installed our an alternator on a 2001 Chrysler PT Cruiser for his customer. AC tests are made for AC volts while tests for DC charging output are made in DC amps. Free run starter draw on red scale. One of the most important circuits in the 24-volt electrical system in any vehicle or piece of. Please read the entire procedure before starting. But AutoZone and other stores will charge and test it for free, so it may be easier to take the battery to them. I think you can do a similar test without an inverter by starting the motor and then turning on every dc appliance you have - lights, fans, electronics, etc. Then start the truck up and make sure belts are tight and nothing is slipping. If the alternator was bad, then driving to autozone and then back could be enough to drain the battery - particularly since it sat for a few days after that. If you lose a single diode, the alternator would behave in just this manor. It never dipped below 14. Learning how to check your motorcycle's charging system is way simpler than you might think and at most takes about 1 to 2 minutes. Connect the red probe to the anode and black probe to the cathode. How to test your alternator Car alternator, if you don't know what one is then take a look at our article what is an alternator. When this kind of test is being conducted, you will have to look for a shift towards the left by the waveform of the testing phase. Getting Started with Your Multimeter Multimeters are the perfect tool for troubleshooting electrical problems in anything from industrial to household devices. This is a simple test we can do to check whether it is good, open, or shorted. So we take the ohmmeter and place it across the leads of the diode. I do not know what you are hoping to achieve To carry out a meaningful test you need a voltmeter to measure the output volts an ammeter to measure the output current and a means of applying a appropriate load to the alternator. 04 volts less. 3)Had the local parts shop do a load test on the electrical system, they told me I had a bad alternator. A higher reading indicates damaged alternator diodes. 2015 Dodge Dart 2. The diodes are the electronic part of the alternator that convert AC voltage to DC. The surge will fry your computer. I still can't find a clear guide how to test the alternator with a multimeter (that is what I need to do, right?). If it's more than seven years old and you'll be traveling alone without easy access to a jump, replace it. Fuel injection has helped prolong the service life of starters by allowing engines to start more quickly when they are cranked. Checking Alternator Voltage Output with a Multimeter. 4 with engine running. The alternator disconnected from the battery test isn't a good idea the alternator depends upon having the battery power source/load for it's regulation as well as stable voltage field excitation power supply. I have seen known bad batteries and alternators test good and vice versa. You don't have to disconnect. How to Test a Diode using a Digital Multimeter The diode testing using a digital multimeter (DMM) can be carried in two ways because there are two modes available in DMM to check the diode. Connect the red probe to the anode and black probe to the cathode. A multimeter can be used to quickly test or diagnose a failed alternator. How to test a car battery without a multimeter The easiest way to test a car battery is to use a battery analyzer or also known as an electronic or conductance tester. Your equipment needs for this are very simple. So it's important to know how to test a car battery. There are also voltage checks that need to be made. PS -- My alternator went at 165,000 miles ('03 Pilot). A volt/ohm meter can be used to check the resistance of the series windings connected between the two commutator bars of each coil. If you're tempted to test an alternator by disconnecting the. Digital Multimeter Amp The Innova Digital Multimeter Amp Probe Is Ideal For Testing Alternator Output, Starter And Battery Current Draw As Well As All Other Electrical Wiring Circuits. This is the sound of a bad alternator. If your alternator isn't working right, you could end up stranded in the middle of nowhere. Your alternator is a vital part of your engine, if it's not in tip-top shape, then your car is bound to be the stressor of your day. How Accurate does a Multimeter Need to Be? If you are an electrical engineer or a technician who will also be using a multimeter to test and repair printed circuit boards or electronics, then you need an accurate meter. Checking the Car Battery When the Engine of the Car is Running. Using a voltmeter is one of the most practical and most accurate ways you can determine the condition of your car's alternator. Alternators don’t always go bad in the exact same way. It's usually caused by a ground connection that is less than ideal. Here's how to use a digital multimeter when working on your car. As you drive along the belt driven alternator takes over the role of delivering power to the car's electrical systems and also recharges the battery. If you lose a single diode, the alternator would behave in just this manor. The back of the alternator has several wires connected to it, unless it is a single wire system. Positive output on your alternator and your positive battery terminal and also with other connections. The alternator must be running to test without disassembly. com › GM › 3. Leave the jumper wire connected from DF to ground. You should not do this in order to test the alternator by seeing if the car still runs or by checking the voltage at the battery. Here's how. if your voltage readings are less then the alternator output is low. One test is a voltage test. In the photos of this article we used a more expensive Fluke multimeter. Re: Alternator Testing - Idiots\' Guide Please Dogwatch says you should see 14. I have a 1995 Ford Taurus Wagon GL with a 3. Hmmm? Battery is good, Alternator is good, but will not charge.