How to Use an Automotive Test Light - Quick and Easy

hey everyone Joe here and today we're gonna be learning how do you use a test light it's a pretty easy tool to use and if you ever work on your car's electrical I recommend you have one in your toolbox so let's get started here we have a classical test light it consists of a bulb inside you can see that ball right in there on one end it's connected through this metal probe in the other end through a wire to this clip right here the most common way to use a test light is to connect your clip end right here to the negative end of the battery which is sometimes called ground or chassis and you take your probing side and you start probing connections that are connected to the positive side of the battery which is sometimes called power or 12 volts if I poke this probe to the positive turn awry here we can see that I completed the circuit and the light bulb lights up so I know that this spot is connected to the positive end of the battery the other way to use a test light is to connect your clip end to the positive end of the battery and use your probe end to start hoping for connections that may be connected to the negative end of the battery so in this case this lights up and I know that this spot is connected to chassis or the negative and the battery likewise if I connect my probe to this piece of metal here this is also connected to the negative end of the battery a common application for a test light is to check to see if a fuse is blown so for example I have my fuse box underneath the dash over here inside the car I'm gonna take my negative end of my clip clip it to a piece of metal nearby and using the probing slide I can check to see if a fuse is good or bad so for example if I probe this it lights up I probe this spot here it also lights up telling me that this fuse is good so the test light that I've been using this video is an older-style test light for the fact that it's using a light bulb the newer ones actually have LEDs inside them and if he focuses on here you can see there's one LED here and another one here this is to show you that you're either hoping a power or a ground connection this is a nice feature but the real reason why modern test lights use LEDs is because they use less current the older style ones that use a lightbulb will draw more current than the LEDs this is important because if you were to probe the wrong wire in a modern car you might be potentially drawing too much current from a wire connected to the computer and be damaging the circuits inside therefore if you use a test light that has LEDs in them you have a less chance of damaging your car and just to demonstrate to show you how the LEDs illuminate I'm gonna first test your power and we can see that I have a red LED on and reverse of the connections you can see that I'm testing that for ground and angry LED illuminates if you want to buy a test light of your own you can easily find them at your local auto parts store like Advance Auto Parts napa auto zone you can even get them at Walmart Target Amazon whichever store you prefer if you're paying nine to fifteen dollars that's a pretty fair price anymore and you're probably paying too much with that being said I'm gonna show you some different types of test lights that you can buy and if you look at the one over here this looks just like mine it's not exactly like mine but it's very similar to it it has a medium sized probe it has a clear handle so I can easily see if the bulb is damaged or not or it's connected it has a spot where I can take it apart to get to the bulb to service it which is pretty important you want this for your test light it has a strain relief for the wire so that you can't easily break off the test light it has a straight wire instead of a coiled wire more on this in a bit and it has a alligator clip that looks like this this is my clamp of choice I just feel like it makes a better connection the clamps I'm not too fond of in a test light look something like this has a spring in the middle you push down and these jaws open up doesn't the other one but in Reverse way it doesn't seem to make a really good connection when I've used them in the past they easily slip off from the internal chassis of the car and it just makes it pretty cumbersome to work with so I don't really prefer these at all here's an example of a test light with a coiled wire coil wires are pretty cool because you can have a longer length wire in a small profile coiling the wire up makes it easier to put in your toolbox and makes it long when you need it I don't really like them because it just feels kind of spring when I'm pulling it around so that's just my personal preference and what's cool about this test light it actually has a little jacket around the needle here at the probe which makes it harder to short-circuit on the side the last test that I want to show you is the LED test light as mentioned before these are a computer tolerant or computer safe test lights it had you pierce the wrong wire in your car and it was a sensitive computer wire you would draw more current than usual with a light bulb test light with an LED Tesla would draw less so you have a lower chance of damaging your car's computer or any circuits that are not tolerant of high currents it has the same kind of alligator clip that I'm fond of it has the straight non-coal wire it has a okay strain relief but that's okay and I liked how to has a shroud around the point of you here the only thing I don't like about this test light is that I can't replace the LEDs inside and then it seems to be a common theme with test lights that use LEDs they don't give you a spot on the bottom to unscrew and replace the LED circuit board or any LED himself but overall I would suggest an LED test life for beginners simply because it's more computer safe and you can avoid accidents thank you so much for watching the video if this helped you get more familiar with the test line or helped you in any other way for troubleshooting your car's electrical system consider giving the video a like also consider scrubbin to my channel for more helpful DIY tips if you have any questions at all please leave a comment below

Channel: JoeCanDoIt

Views: 557,596

Keywords: how to, test, automotive, test light, how to test, how to use a test light, how to easily test automotive electrical circuits, how to test a failed battery or alternator, how to test an alternator with a multimeter, how to use a scan tool, how to use a multimeter, light, how, to, automobile (industry), automobile, how to find a open circuit, using a multimeter to test an alternator, how to wire a relay

Id: bmCGgDtCAYA

Length: 6min 9sec (369 seconds)

Published: Wed May 16 2018