Test Light (16) Digital Storage Oscilloscopes (14) Optical Power Meters (14) Power Sources (14) Electrical Testers (13) Handheld Oscilloscopes (13) Resistance. Convenient closed case calibration allows ad justments to be made directly through the Optically-Isolated RS232 serial port. no bench test for regulator/rectifiers, test AC output from the stator. Re: Test Alternator Output in reply to IH2444, 08-08-2006 06:57:05 quick and dirty test. Large digit display with bright, two-level backlight makes the Fluke 88V significantly easier to read than the old Fluke 88. Locate your alternator and check to be sure the alternator belt isn’t loose. Analogue multimeters have been in use for very many years and sometimes go by the name VOA as a result of the fact that they measure volts, ohms and amps. To get your alternator diagnostic on the way, the first you need to do is check what the battery's voltage is with your 2. The 'proper' test, other than by actually measuring the amperage which is not easy with an alternator if there is no permanent ammeter installed and risks damage to the alternator (momentary disconnection on load will blow the diodes instantly) is to load a charged battery at about 10 amps for 5 minutes (5 amps for 10 minutes will be the same!). I took the alternator off last year and took it to the local implement dealer who sent it out to be tested. A fresh battery and a malfunctioning alternator, however, will quickly leave you stranded again. Run engine at 2,000 rpms for tests and turn on the blower fan for the AC or Heater, the headlamps, and any other accessories that put a strain on the alternator, and watch the gauge to see if it decreases voltage or amperage. Your car alternator will not last forever, and when it does go, it can leave you stranded somewhere with a flat battery - and no-one needs that. Car Battery Load Test Procedure. the current will have flown outside the alternator through its carcass, not through its internal components or winding's. Dimming Lights The alternator by itself can be the cause of dimming lights, fading radio, and/or stalling. A lead-acid battery has certain defined characteristics than make it easy to evaluate the health of the charging system without fancy test gear. Pop the hood and check the battery, and you might think you've found the culprit. How To: Measure current, voltage, resistance, and continuity using a multimeter How To: Use a multimeter and check for ground How To: Make a glowing ice bulb from a balloon How To: Use a multimeter How To: Test a starter capacitors in your car How To: Test a vehicle alternator with a standard multimeter. You can remove the discharged battery and replace it with a fully charged one or simply charge the vehicle's battery (on the vehicle or off) before test. Car Battery Voltage Drop. No multimeter needed. Let the people with 12+ years of experience in finding and buying car parts help you find the best Alternator for your Honda Civic. How do you. 2 volts or less. If voltage is present one or more diodes has failed and the alternator should be replaced. To test the alternator on the 318, place the black multimeter lead into the COM port of the multimeter and the red lead into the AMPS port of the mutlimeter. You need a digital multimeter for this test. Features • Testing functions include: O2 Sensor Test, Ground Test, Battery and Alternator Charging Systems Test, and Battery Drain Test • Accurate RPM measurements for 2 and 4 stroke automotive engines with 1 to 12 cylinders using the inductive pickup • ms-pulse Width function to test on-time of both PFi type and TBI type fuel injectors. 1 volts shows high resistance in the circuit. If the old alternator passes the tests, the problem is obviously not the alternator, and you’ve missed something. Once reserved for engineers and electronic technicians, multimeters—sometimes called “multitesters”—have come down in price and size, making them indispensable for homeowners who have basic knowledge of circuitry. It is fairly easy to test a regulator on the alternator (i. 9 on Freightliner: Alternator R&R They may be out there, but my Google-Fu must not have been strong enough. One test is a voltage test. Today we're going to talk about an alternator ripple test. A good alternator should measure less than. The fast and easiest way to test an alternator with a drill, a socket and multimeter this way by spinning will produce electricity and therefore test for its functionality Please like a share. terminal on the back of the alternator, (not at the battery). Any idea what could be causing this?. As an added bonus these also can measure AC current through the clamp, as well as AC and DC voltage and continuity check through test leads. 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. Volts are the capacity of a given electrical current, and amps are the current's power. Features • Testing functions include: O2 Sensor Test, Ground Test, Battery and Alternator Charging Systems Test, and Battery Drain Test • Accurate RPM measurements for 2 and 4 stroke automotive engines with 1 to 12 cylinders using the inductive pickup • ms-pulse Width function to test on-time of both PFi type and TBI type fuel injectors. How to troubleshoot a pump control panel with a thermal multimeter. Without a functioning alternator, the vehicle quickly uses up all of the battery's capacity, leaving it drained. Turn the rotary switch to the range needed. Shopsarahmac sells a wide range of items, from dress, electronic, accessories to all another products. A diode is forward-biased when the positive (red) test lead is on the anode and the negative (black) test lead is on the cathode. At the factory we have custom made testing equipment to test each component separately. Locate your alternator and check to be sure the alternator belt isn't loose. DIY how to test a BMW E39 battery & alternator (discussion) Compliments of bluebee @ bimmerfest. Richpin demonstrates how to test an alternator with a standard multimeter. Unlike other similar products on the market, this is a mini device that comes with a practical kit. Then the tester added load drawing more current from the alternator. It's rated at 12v, 1 amp for output, and I tested the voltage and that's at 15v, which I assume is within the proper range. If it's in the 13- to 15-volt range, your alternator is fine, and you need a new battery. 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. If these checks do not reveal a fault, disconnect the battery earth terminal and check the alternator leads with a voltmeter. We test for a voltage drop by back probing across the suspected source. 88890074 Multimeter General alternator information Alternator voltage must be limited to prevent battery electrolyte from evaporating. You would first want to rule out that your battery is not bad before you decide to replace your alternator. on the running vehicle. If you are looking for Car Battery Load Test Procedure, you’ve come to the right place. Min/Max and Hold buttons save retrieved data. Most multimeters include a settings option for measuring current in amps. If the engine cuts off, it is a sure sign that the alternator has died. Finding a voltage reading that is above 0. Yours is clearly the latter although the manual I have located on line for your engine only refers to the alternator type (post1976) and the mechanical type! Check that you have a power supply to the tacho ( in addition to any for illumination) check the wiring to the sensor and all connections. And when I test a good alternator the reverse voltage shows OL like it should so I know my diodes are bad it just doesn't appear to show up as a draw. The voltage spikes are something to check into. Perform the Basic Charging System Health Test above. Take the negative lead of the multimeter and put it on the negative post of the battery. The alternator must be running to test without disassembly. I went to an auto parts store to test one of their alternators to make sure I was doing the test correctly. They said they checked all the wiring and everything tested good. I am trying to measure the amount of electricity produced by the alternator with a multimeter. If it’s in the 13- to 15-volt range, your alternator is fine, and you need a new battery. We have a broad range of avr alternator and services which can be sourced by this comprehensive vertical web portal dedicated to helping global buyers searching and purchasing from Taiwan and China avr alternator manufacturers. Set the multimeter for a two-cycle motor and set the meter for a single cylinder. A simple test to check the working of the alternator is by running your car; and then unplugging the positive connection of the battery. Multimeter is set to 200V AC. Remove the panel cover under the hood. By creating an account you agree to the Hunker. If good, the voltage drop should be 0. Dimming Lights The alternator by itself can be the cause of dimming lights, fading radio, and/or stalling. The reading of each combination should be the same (test leads 1-2, 2-3, and 3-1). Locate your alternator and check to be sure the alternator belt isn't loose. Get a multimeter and set it on DC ( direct current) with the car turned OFF , put the red lead from the multimeter on the Positive + battery terminal and the black lead on the Negative - terminal. No further testing is required, since this multimeter test result eliminates the alternator on your Honda as BAD. Or am I taking the term "without an alternator" too literally?. It is an easy task, and pretty much any multimeter can do it successfully. 3L Ford Ranger's engine running. Connect the LED in forward biased with multimeter test leads i. 8v with no load on it. Tools needed: Multimeter. Confirmed that the voltage regulator is getting 10 to 12 Volts (TEST 3). Accessory for multimeter. With a spinning alternator (hooked up per my previous instructions) the first test is whether it maintains the voltage between 14. open the alternator and check the diodes. How to Find a Parasitic Battery Drain. Then test after an overnight rest. Direct current may flow through a conductor such as a wire, but can also flow through semiconductors, insulators, or even through a vacuum as in electron or ion beams. Dont know. The best automotive multimeter is the Fluke 87-V, which is safety rated at CAT III 1000V, CAT IV 600V and suitable for testing alternator diodes, duty cycle, solenoids, breaker points, wiring, switches, and more. You will need one piece of equipment for this test though, a multimeter. If you are looking for Car Battery Load Test Procedure, you’ve come to the right place. First select diode mode in your multimeter then connect anode lead of multimeter to anode of diode and common lead with cathode of diode, Your multimeter will show you knee voltage of diode. I have seen known bad batteries and alternators test good and vice versa. How To Test A Car Battery With A Multimeter: Batteries lose charge over time and replacing them can be expensive. Today, you risk frying every electrical device in your vehicle. It should be higher than before, between 13 and 15 volts. OK, the test is divided into three parts: PART 1- Testing the alternator voltage output with the multimeter in VOLTS DC mode. Load and alternator test; Very easy to use; Works on cars, trucks, vans, boat, SUV. How to test an alternator If you want to test an alternator all you need is a digital multimeter. 6 Ways to Check a Capacitor by using DMM & AMM (AVO). To test the throttle position sensor: Set the rotary switch to N. Car Battery Load Test Procedure. Lift the seat on your. I took it for about a 30 minute round trip ride at highway speeds hoping the alternator would charge the battery but the light never went off. These can be had for as little as $15-$20 online or at places like Super Cheap and a cheap one will certainly be ok for what we are doing here. 99v minimum. Got it towed home and had oreillys test the battery and alternator and they said both passed fine. Repeat LOAD TEST. Fluke 15b Digital Multimeter Tester DMM With Tl75 Test Leads F15b. (However usually the engine will stall if it is going that slow). Let the people with 12+ years of experience in finding and buying car parts help you find the best Alternator for your Honda Civic. To get an idea of it's amperage capability, also test it with headlights and heater fan running, engine revved up a little. That means the alternator is pumping out the juice. Richpin demonstrates how to test an alternator with a standard multimeter. 5 VAC with the engine running. The back of the alternator has several wires connected to it, unless it is a single wire system. If the old alternator passes the tests, the problem is obviously not the alternator, and you’ve missed something. 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. Whether you need a model for small tasks or models for big commercial jobs, digital and analog multimeters give you the tools you need. A multimeter must be connected in parallel in a circuit (see diagram below) in order to measure voltage. 15” between legs): Small Case. 2 months ago I put a capacitor of 2 farad for the sound. The tests will help you to identify or eliminate the stator as the problem in a charging issue. Most uninformed know as much from electricity as a cat know of saffron and it scares them. It is designed to help you accurately identify engine problems as it tests switches, wiring, breaker points, solenoids, duty circle, alternator diodes and many more. If it's an overrunning alternator pulley, you should be able to easily turn the pully in one direction and spin the alternator, but in the other direction the pulley should easily "freewheel" WITHOUT spinning the alternator itself. without replacing any components. It can test AGM, GEL or Lead Acid and can test charging systems 12 and 24 volts. We are much harder on a alternator than a car or even a 18 wheller. A voltage regulator will limit the maximum amount of voltage from a power source and prevents a device or alternator from. One or both will be used to check the health of all Briggs & Stratton alternator systems. Check the alternator gauge. Car Battery Voltage Drop. Direct current (DC) is the unidirectional flow of an electric charge. I pulled the alternator and had it tested and all is working correctly. If the fuse is not good, replace it. 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. You take a digital multimeter, check for voltage (should be between 13. Take a look below at the average quote on WhoCanFixMyCar. next start the engine and let it idle, set the meter up to measure the voltage again, it may still be 12. Touch the positive(red) probe to the metal connector inside the spark plug housing. You can also troubleshoot your. 5 Volts battery voltage with the engine running. Let the people with 12+ years of experience in finding and buying car parts help you find the best Alternator for your Honda Civic. If you need more information on measuring resistance, check this article here. 12 v alternator manual w 90series drawing 1. The meter readings also let us know the switch is in excellent condition with virtually no internal resistance. If your battery is good, and your alternator isn’t working, the battery will still lose its charge because the alternator isn’t keeping it charged. This is not a be all / end all test for the alternator but is a good place to start. If the alternator is functioning properly, the voltage displayed on the meter will be around 13. 0L Mercury Mountaineer isn't hard. Only when the load on the system goes down, will the alternator (through the action of the voltage regulator) reduce the charging voltage. It can test AGM, GEL or Lead Acid and can test charging systems 12 and 24 volts. It is important to know how to test a car battery with a multimeter for normal battery issues. A higher reading indicates damaged alternator diodes. Alternator light on means the alternator is drawing more power than it is generating, THIS may be due to a faulty alternator, slipping drive belt or just flat low engine speed. The result can often lead to a flat, caused not by a faulty battery or through something obvious like the headlights being left on. This test will determine whether or not the system is charging the battery and, if not, whether the alternator or regulator is at fault. A multimeter set to the Resistance mode (Ω) can be used as an additional diode test or, as mentioned previously, if a multimeter does not include the Diode Test mode. This electrical connector provides electricity to the field windings in the alternator and is required for it to work properly. They said they checked all the wiring and everything tested good. If the voltage is the same as or lower than before, then the alternator is most likely toast. embedding without our logo. Trace the fuel pump connector at the back of the car and test for incoming voltage using a digital multimeter. A diode blocks current from flowing in one direction, while allowing it to pass through when the polarity reverses. A bench test will check the diodes and internal regulator and then tell you if the alternator is capable of producing its rated current and voltage. Now we now know how to route wiring to and from the switch. From the right post (the "run" key position), we'll connect leads to the coil in the primary engine ignition system and the alternator. Voltage drop testing is always done with the circuit, under a load. Replaced the alternator again still the same results. With your top alternator disconnected, you may very well have been reading your 12. The sockets at the bottom used to plug the black and red test probes into. If the alternator is going bad, you will notice that dashboard lights appear dimmer than usual. 6 out of 5 stars (10) Total Ratings 10, $79. It should be higher than before, between 13 and 15 volts. If you have a multimeter on hand you can use the multimeter to get a reading of the voltage that your vehicle's battery is currently putting out. uk: Car & Motorbike. A multimeter is a great tool that everyone should take the time and learn how to use properly. Stress test the alternator by turning on the car's radio, headlights, and air conditioner. if your voltage readings are less then the alternator output is low. Or, if you are mechanically adept, try the following yourself: While the engine is running, use a multimeter to check the charge at the alternator output. The orange wire is B+ and the black wire is B-. 6 v under a variety of load conditions. Take the negative lead of the multimeter and put it on the negative post of the battery. Run engine at 2,000 rpms for tests and turn on the blower fan for the AC or Heater, the headlamps, and any other accessories that put a strain on the alternator, and watch the gauge to see if it decreases voltage or amperage. If your alternator is broken or otherwise not working, for instance, it won't charge the battery as you drive, in which case the battery will simply die. If you are looking for Car Battery Voltage Drop, you’ve come to the right place. So good luck, be careful, and enjoy!. I want to test my generator to see how many amps it's putting out at idle. apply battery power. How to Test a Silicon Diode with a Multimeter. D-TAC™ PLUS continuously monitors battery requirements, and automatically charges the battery as needed—as fast as possible without damage or “boiling. If you find that the fan in your car only works on high, you might well have a broken one. I have yet to test it with a multimeter. Do Replace alternator Exceeds spec. Testing these things requires a big electric motor capable of spinning the alternator while under load- probably about 3hp at a couple thousand RPM. Working Principle Also Explained. Touch the test probes to the circuit or device under test and read the resistance on the display. How to Test a Stator Pickup on Riding Mowers Check the output, which should always be at least 30 volts. 8L Ford Mustang. If the battery holds a charge when it's not connected to the car - something is draining the battery far faster than the computer memory and digital clock. Measure the alternator amperes output using your multimeter as before. DIY how to test a BMW E39 battery & alternator (discussion) Compliments of bluebee @ bimmerfest. 50 for a complete 27si rebuild kit. First make sure that the vehicle's battery is fully charged. You don't have to disconnect. "After reading the web page ' Car electrical ' all the questions i was gonna ask were answered for me in the detailed text. How to check the alternator with multimeter The alternator's job is to produce electricity and charge the battery. Besides the possible damage to a good alternator, if the alternator is not producing full voltage, but just enough to keep the engine running, you'll never know it using this method. won't tell you how much,but just quick test to tell if it's working at all. It is very possible that there was no alternator output and I was just measuring a bad battery at 9 V. This ON CAR TEST doesn't require any tools, such as a multimeter or anything else. Multimeter is set to 200V AC. The alternator will be fine. Use the other multimeter probe to make contact to frame ground. Re: Test Alternator Output in reply to IH2444, 08-08-2006 06:57:05 quick and dirty test. The final test you can run is doing a reverse circuit test where you do not remove the cables from the devices they are connected to and then test between the battery terminal and the device. It should read 12V. Any simple diode will exhibit a ‘front-to-back’ ratio since they are designed to allow current to flow in only one direction. 8 V is low but for this car its not. The PHA certifies that it will carry out the public housing program of the agency in conformity with title VI of the Civil Rights Act of 1964, the Fair Housing Act, section 504 of the Rehabilitation Act of 1973, and title II of the Americans with Disabilities Act of 1990, and will affirmatively further fair housing by examining their programs or proposed programs, identifying any impediments. 5 idle and 12. A higher reading indicates damaged alternator diodes. Run engine at 2,000 rpms for tests and turn on the blower fan for the AC or Heater, the headlamps, and any other accessories that put a strain on the alternator, and watch the gauge to see if it decreases voltage or amperage. I read you can test terminals while running and if it's under 13V in general then alt is bad. Voltage drop testing is always done with the circuit, under a load. If you are looking for Car Battery Voltage Drop, you’ve come to the right place. A simple test to check the working of the alternator is by running your car; and then unplugging the positive connection of the battery. I have a charger on the battery right now. MICTUNING Digital Multimeter, DC 6. 7V, then the alternator is bad and needs to be replaced. As motorcycles get older, the electrical systems often need repairs, or at times, complete replacement. If your alternator is broken or otherwise not working, for instance, it won't charge the battery as you drive, in which case the battery will simply die. 7V if it does replace the battery. Testing the Alternator When You Don’t Have a Voltmeter. Take it to a professional for a final diagnosis. We test for a voltage drop by back probing across the suspected source. When I got back, I made sure that both connections were good. 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. A multimeter car battery test is one way to take a deeper look into the problem. Less than 14 volts and you have something wrong with your charging system. Disconnect the regulator connector, and devise a way to jumper the two connector wires together. That means the alternator is pumping out the juice. This test will determine if the alternator is charging the battery at the proper levels. Alternator. Although electrical systems are generally reliable, age will have its effect on the wires themselves at places where there is consistent movement—the wiring harness as it passes from the frame to the headlight is being a typical example. Try to buy one equipped with an amp clamp. Whether you're on the side of the road or tuning up your car in the garage, use the best alternator testers for cars and trucks to keep track of your battery and know when to replace it or repair. Consult your repair manual or factory service manual (FSM) for all the test ratings. The easiest way to test an alternator is to check the output voltage, and a lot of instrument clusters even include built-in voltmeters. As pointed out by @tlhIngan, use a multimeter to test the alternator. Solid state electronics don't react well to the voltage surge that results when the battery is disconnected while they are on-line. "Posted results above". , Hitachi, Lucas. All the regulator does is connect the brushes to the supply until some voltage (between 13 and 14 volts) is reached. Innova 3340 Automotive Digital Multimeter. In case of digital multimeter, set the meter on “Diode Test” Mode (in case of analog multimeter, set the multimeter on Resistance or continuity mode) by turning the rotary switch of multimeter. The belt was very tight. 1995 Ford Taurus: My battery. 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. 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). 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. Test every lead of the stator's connector and note the readings. Set the parking brake and shift the transmission to Neutral (manual) or Park (automatic). Although electrical systems are generally reliable, age will have its effect on the wires themselves at places where there is consistent movement—the wiring harness as it passes from the frame to the headlight is being a typical example. 3 volts (engine running, lights and accessories off). There isn't really much that you need, just a tester or DVOM and some time. Testing Your Charging System. Other vehicles sometimes have handy warning lights on the dash that turn on whenever the output voltage of the alternator drops below a certain level. In any case, buying an alternator rebuilding kit instead of replacing the whole thing might be a good solution. I still can't find a clear guide how to test the alternator with a multimeter (that is what I need to do, right?). on the running vehicle. The test indicated that the alternator was not charging at all. Luke, I think your battery maybe bad. and Do alternator test again if necessary alternator this suggests a shorted starter without To Use of Multimeter Text. Craftsman Industrial Multimeter Test Leads 9V Battery with Case LCD Measure Tool $104. How to test a car battery yourself. Here's how we can check a charging system with a few simple pieces of equipment. charging system. 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. Connect the high amp clamp into PicoScope Channel A, select the 200 A range and zero the clamp. CASE 1: Your test result indicates 13. If you are looking for Car Battery Load Test Procedure, you’ve come to the right place. A voltage regulator will limit the maximum amount of voltage from a power source and prevents a device or alternator from. This next tutorial is going to show you just how easy it can be to check your vehicle's alternator. Types of Charging Systems. 5 volts above battery voltage), repair wiring harness from alternator to regulator. worn alternator can test ok on voltage, but will not keep battery charged, if you're using the power elsewhere. How to test your alternator. Learn how to give them new life with our step by step battery reconditioning guide. Today we are going to discuss how and why to perform a voltage drop test. Clamp Multimeter How To Use For Dummies is an Illustrated Guide on Measuring Current on a Wire of a Gadget. Test the ammeter with the connections + from battery to + on meter and - battery to - meter and note the ammeter needle deflection. If it drops under 9 or straight to 0-3VDC, the battery is bad. How to verify electrical test tool operation with a proving unit. Re: How to bench test an alternator / diagnose a starter « Reply #2 on: 14 December 2011, 02:32 AM » You should be able to tell if an alternator is working by connecting a multimeter to the positive and negative terminals of the battery. This tutorial will show you just how to make use of a digital multimeter (DMM), a vital tool that you can utilize to diagnose circuits, learn more about various other individuals’s electronic layouts, and also even test car lights. No further testing is required, since this multimeter test result eliminates the alternator on your 2. If the battery holds a charge when it's not connected to the car – something is draining the battery far faster than the computer memory and digital clock. Using certain multimeter models, you can test to be sure that components — such as diodes, capacitors, and transistors — function properly. It can also be a bad alternator. A diode is forward-biased when the positive (red) test lead is on the anode and the negative (black) test lead is on the cathode. You should read zero ohms with the test leads connected one way, and very high (infinite) resistance with the leads reversed. 15” between legs): Small Case. Conductance Cable Verification Test} Uses conductance technology to calculate the voltage drop across the positive (+) and negative (-) sides of any circuit and total circuit drop without running the engine} Preset tests for battery ground, starter and alternator circuits, and user-defined test are available. Alternator and Starter Diagnosis Rotating electrical parts such as starters and alternators often have to be replaced on older, high-mileage vehicles. Car Not Starting? Find Your Culprit By: Eric Wasson Testing your battery is very important- it can help ensure that your battery will function when you need it most. 5 Volts battery voltage with the engine running. Most multimeters include a settings option for measuring current in amps. com offers 201 ul multimeter products. Start the engine, and touch the red and black test leads to the battery. Touch the black probe against the first point of the circuitry/wiring. At 2000 rpm, should be 13-14 volts, if its ever below 12v the alternator is not charging. The Introduction. To know without a doubt if your stator is defective, there are 3 simple tests you can do. If the voltage is the same as or lower than before, then the alternator is most likely toast. I have tried several times to attach the multimeter to the alternator but I keep getting the reading of 12. Resistance mode: typically used only if a multimeter is not equipped with a Diode Test mode. Over the years, car manufacturers have learned how to minimize the possibility of a dead battery: by getting headlights to turn off by themselves, for example. Here's what to do. 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. With the engine at 2000 RPMs, the meter should read between 14. The alternator must be running to test without disassembly. You don't need more than a multimeter to be able to test the alternator and all the test steps are explained in a step-by-step manner. Get free 2-day shipping on qualified Multimeters products or buy Electrical department products today with Buy Online Pick Up in Store.