Beginners guide on using electrical multi-meters for autos

you hey guys it's Russell back with diesel giant calm on today's video I'm talking to beginners and we're going to talk about multimeters and how to use them you know if you want to do any type of automotive work or troubleshooting you need to be able to work one of these a multimeter if you've never used one of these before if you've never even seen one before they can be kind of intimidating they have a lot of settings on them they have digital readouts they've got some probes that come with it but I want you to learn how to use this because they're not hard at all they're very easy and this basically is going to be a beginner's overview of how to use a multimeter to troubleshoot items that are on your car your car's electrical system so stay tuned next as I show you how to use this multimeter okay guys this is a typical standard multimeter this one is a Sears Craftsman unit it's the model number is eight two zero two five I've had this for about twenty five years I don't even know if they make these anymore but it doesn't matter you can find these at pretty much any automotive supply store like Advance Auto Parts Pep Boys you can buy them online what I want you to do is I want you to get a good basic multimeter like this it doesn't have to be fancy these I believe are under about thirty dollars and this is this is basically all you need to troubleshoot most electrical common electrical problems that you're going to have on your car I'm going to go over this just real basic and just try to give you a little explanation about what these different settings mean right here is what you're going to use on most of your automotive that stands for volts DC which is direct current now AC is what you have in your house in a nutshell the difference in the current is direct current moves in one direction the electricity usually flows from negative to positive now on AC that you have in your house it's called alternating current and it moves the electricity flows backward back and forth really really fast that's all you need to know about that just know that the volts DC is what we're going to use on troubleshooting a lot of our electrical on our cars now you see these got different scales all right and usually when you turn it's basically moving the decimal point for you all right if you get into the higher voltages so what I usually use on a car is 20 because you're not going to get pretty much anything over 20 volts on anything it's a 12-volt system so it so give you a good readout so I usually use 20 your scale is probably going to it may look a little different but try to get close to 20 we could use 200 that would work also but this way it'll give us like 12.25 volts instead of let's say 12 point 2 or 3 volts so it just gives us a little bit finer gradient to work with now right here you see it says ohm and it's got that little symbol it's a like an upside down horseshoe we're also going to use that for automotive work to test resistance now all resistance is it means what kind of resistance to the flow of electricity if you've got electrical going through something that has no resistance which there are always going to be some resistance but the more narrow the gauge of wire the harder it is to push electricity through it so that's how come you see battery cables they could be huge okay and you would think that those would have more resistance but it's actually opposite it's easier for the electricity throat to to go through such as your starting cables a battery cable that's really big as opposed to one that's really small and I'm going to show you what these with these mean as far as with your with your car so will not Worr yourself so much with the the scale but as I said before volts DC and homes this is what we're pretty much going to be concerned about today as far as doing some checks on your car now your leads you're usually probably going to have a which generally considered this is the positive lead and this is the negative now don't be worried if you hook something up backwards if you're testing voltage because it'll just read with a minus sign it's not going to hurt your multimeter at all what I do want you to be concerned with is I would like for you to make sure that any time you're testing voltage all right you never put it on the ohms because that could blow the fuse when we're testing ohms the meter has a battery inside here that gives a little bit of electrical current so that we can test resistance if we let's say have this - 2 ohms and touch our battery it could blow the fuse inside the multimeter we don't want to do that when we're testing volts we're testing something we're basically measuring electricity here we're measuring the resistance this we're measuring the actual electrical power there is another thing that you can use this multimeter for as I said before where it says volts AC and that's what you would use to test let's say a plug in your house current please be very very very very careful when you plug these in and I'm going to show you how to do that but when you plug these into a socket make sure that you don't have any breaks in the wire make sure this is not cracked this is insulating you from the electricity and if one of these wires are something had a break in it you were to touch your hand to it under the right conditions you could get a really nasty shock and you don't want to get shocked from 120 volts it hurts so I'm going to set the camera up now I'm going to show you how to test the most common thing automotive and the simplest thing you probably first use your multimeter is to test your car battery with okay guys we're going to test a car battery now this is a normal 12-volt car bad that can be found in any type of passenger car as I told you before we're going to be checking volts and I have my gauge set on 220 so here's how we do this you find which of your terminals is positive and which of them negative normally you'll probably have a red battery cable or some type of indication but please look on your battery it'll have a plus symbol and where your negative terminal is it'll have a minus symbol so oftentimes the cables will be read on positive but not always and don't go by that go by what it says on the battery so we know that this sides are positive we know that this side is our negative so we're just going to touch the terminals just like that and read the results this says thirteen point one five volts now you're probably asking yourself why is this a 13 and not 12 well if you're reading a battery and it reads 12 volts it's basically dead batteries depending on the temperature the air temperature how cold it is the battery will probably a fully charged batteries about twelve point six or twelve point seven volts I've had this battery sitting on a battery charger because it's been sitting here in the shop for a while and I didn't want any type of degradation since it wasn't running so it's just come off the charger now what I'm going to show you is I'm going to show you the scale we're going to switch it to the 200 okay and see what happens when you touch that it still says thirteen point one all right but as I said before try to get close to around 20 if your multimeter has that so it'll give you give it to you in hundreds so right there thirteen point four now as I said before what happens if you accidentally get the leads mixed up all right I've got the negative lead for the meter here I've got the positive lead I'm going to touch the negative to the positive and the positive to the negative you notice it still says about thirteen point ten volts but you see the minus sign it just means it's backwards it's not going to hurt the meter at all okay and we just go back and do it like this okay now what you don't want to do is you don't want to touch the ohms when it's on ohms to this it would probably blow the fuse in this multimeter okay so that's the first test your battery test now if you were to run your engine it's going to read a lot higher it may read about 14.5 that's because the alternator would be charging the battery as the engine drink so if you want to test your alternator just have the engine running and touch same thing touch the terminals to the battery terminals and you're going to see what kind of voltage your alternator is putting out if your vehicle is running and you don't see any additional voltage and that means your alternator is not charging and you know what I can tell you this but actually I want to show you this on a different vehicle all right hopefully the wind is not going to be too bad while I'm out here so let's test this battery that's outside and we see we get twelve point twelve point three nine volts now I'm going to go ahead and start the engine and we'll show the difference in the voltage when it's running all right with the vehicle running you see it now says fourteen point about fourteen point two volts so we can see the difference in when the vehicle is often its own so this is a good test if you're not sure if your alternator is charging if you're trying to track down a problem it's something that anybody can do this alternator is putting out basically fourteen point four volts right now so it is in proper working condition I just realized that I had a battery here that will not start the car and I wanted to show you what the voltage is alright see this battery is reading eleven point nine one volts you would think because it's near 12 volts that it's good but this battery is completely at the end of its life it will not start the car and it won't hoard of charge one other quick test that I wanted to show you about checking batteries it's not just related to automotive you can check any type of battery that you have around the house this is a C cell and this is supposed to be 1.5 volts so of course it's got positive and negative so we're just going to hold the leads like so we're going to see what we read all right we're getting one point five two volts so if you've got nine volt batteries double-a triple-a doesn't matter just make sure to set this two volts DC okay and speaking of house current I promised I would show you real quick how to test for current in your house again you're going to put this two volts AC and my scale has 200 or 750 and we know this is going to be 110 and 120 so we're going to turn it to 200 and I'm going to take both of my probes and put them in just okay it reads a hundred and eighteen point four volts alright so that's normal house current again since this channel is automotive related don't go around sticking these in your in your current okay in your in your house it's just dangerous alright so now I want to show you how to check resistance okay now I promised you we're going to check and show you how to do resistance now again I've set my scale on the ohms to approximately 200 right so basically if you see your display like this it's just got a one or it may be it may have a little symbol on it that means it would be the same thing as if there was a short okay or you can say the circuit is open now if I touch the two wires together what it's doing this meter is sending a small amount of electrical energy through the meter and it's reading the resistance of the probes and the wire all right so you can see it says 0.4 that's point four ohms of resistance now there anytime you have something that electrical energy is going through you're going to have some resistance it could be so minut your meter couldn't pick it up but we do know this is standard for this for this meter your meter may read something a little different but 0.5 or 0.4 ohms of resistance between these two wires now again if you're testing something like if I tell em testing this plug and it reads this then that means there's a short or isn't open though could be the wire is broken so if we wanted to test this glow plug I'm going to put one of my leads this is where the pyro would go in right here the power wire would connect here and then I'm going to check the other end of the plug itself all right and we're getting and the reason it's bouncing around is because I may not have a good connection or I may not have it on there real good but it's reading about 1.5 can hold it still about 1 point 5 ohms of resistance now remember the reason that this can glow this is a glow plug the reason that this can glow and get hot is because there is resistance between here and here okay so if I ask you to test your glow plugs on your diesel engine that's one way to do it you could also test between here where it's grounded and here and you get about I can hold it steady about 0.9 arms you really shouldn't if this is the power that's going in here and this is the ground there should really not be any connection there's a little bit just because of the way I'm hot candle it's hard to hold it still but if you wanted to test the element itself well let's just see now let's say the element was broken inside if it was broken inside this is what I would get you would see that it was open okay and again the element itself is it's about it's about one and a half to one point two ohms which is fine so you can go around and test things in your house just make sure all right I don't want to test the battery this has got energy as soon as I put the probes on either side here it very well could blow this fuse out remember when it's in the ohms setting you're testing resistance okay so that's basically what you're going to use for automotive you can test bulbs you can test wires you can test from one one end of the wire to the other if it shows open like this that means the wire has a break in it if you see that the wire has C there's no break it's showing about point that's bounced around about point four okay so we know that there is a path that goes from here into the meter and here the path is not broken if it's open you're touching both ends it's like that then that means that the wire is damaged or something is damaged between this into the probe and whatever else you're testing and this in the program oh the bottom line of this video is not to be to show advanced testing techniques it's to get people that have never used a multimeter arts and they're scared of it to go out and get you a multimeter and this will allow you to do basic testing like I've already shown you so again if you'd like to try to get this model I haven't even checked on Sears to see if it's if it's even available anymore Sears does sell several different multimeters again you can look and see what I've got on here this is not the only multimeter I have but this is the one that I this is my workhorse the one I use all the time and I do testing on glow plugs I test batteries alternators just like I showed you to do on this video so I want you guys to be able to get you a multimeter utilize it and not be afraid of doing it I hope this video has helped those that were intimidated by using multimeter if you have any questions if you have any suggestions for upcoming videos that you would like for me to do just leave a comment in the section below or send me an email contact me on on diesel giant comm and I'll do my best to accommodate you I hope everyone has a great and safe day you

Channel: dieselworld

Views: 1,184,398

Rating: 4.7811818 out of 5

Keywords: electrical, multimeter, diagnostics, auto, diesel, turbo, cummins, powerstroke, duramax, Automobile (Industry), Diesel Fuel (Fuel), Tips, Help, Road, 4x4, Tutorial

Id: RtNMhCzq72M

Length: 19min 5sec (1145 seconds)

Published: Sun Jan 19 2014