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How to Diagnose Your Car Truck SUV - With No Special Tools

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Created on: 2020-07-13

This video shows you some basic diagnostics you can perform yourself without any special tools!

Are you trying to diagnose your vehicle and you don't have any of these tools? In this video, I'm going to show you some simple techniques that you can use to figure out a problem without them.

Now, something really simple. Let's say you have a light bulb that's burnt out. Now, before you go and buy a new bulb, chances are you could have a socket that's burnt out or even a wiring issue. So, you want to find out what's wrong with that. So, if you pull these bulbs out, and this is a 3157. This is out of a turn signal, and you could swap it with the reverse signal. Just make sure it's the same bulb, 3157, so we'll swap those. And then if it works, then you know that it was just a bulb. Now, if it still doesn't work with a known good bulb, it could be something wrong with the socket, or the wiring issue itself.

So, if you have a window that's not working with the switch, whether you have a back window or a passenger side front window, chances are the switches are all the same. What you can do is take the switch out, disconnect the switch. And it may take a little bit of time, but take the other one out of the other side. And then you can try this switch. And if it works, then you know it's a bad switch.

Another thing you can do is check the speakers. If one of the speakers isn't working, most of the connectors are going to be the same side to side. You could switch the speakers. It is going to be a lot of work. But at least you'll know it's not something wrong with the wiring, or the connector, or the radio.

Even relays. If you're having a problem with let's say the horn and it's not working, what you could do is actually find a relay that's got the same number on it and switch them. And then you could test the horn and see if it works, or the AC system, or even the cranking relay. If you have another relay that's the same, just swap it. Start with that. That might work for you.

So, anything you have a duplicate of in your vehicle that you have a known good part, you can always switch it and test the part. Even if you know you have an engine misfire, and you know which cylinder it's on, you could switch a coil, a plug, or a wire with another one and find the problem. Or if you have a friend that has a similar vehicle with the same parts, you could always see if you could borrow some of the parts to test out what's not working.

Let's say your windshield washer pump wasn't working, what you could do is find the fuse for the windshield washer pump, pull the fuse out, and just take a look at the fuse, and just make sure it's connected in the middle. That piece of wire going across a piece of metal. So, that looks good. That's not burnt out. Now, if the fuse was burnt out, you could get a new fuse, pop it in, and see if everything's working. Chances are that's not the only problem. Fuses don't blow on their own. Normally, there's too much current drawing on that fuse, and that's why they pop. So, there could be a wire issue, or the electric motor for the washer system is drawing too much current, and that's what's popping the fuse. Now, if you did find a blown fuse, and you go to replace it, and the second that you put the fuse in, it pops right away, there's definitely something wrong with that circuit, whether it's shorted or the motor is shorted out completely, and something else has to be replaced.

Now, if your engine's running rough, some of the things you should look at under the engine is the wires. See if anything looks burnt, or anything looks loose or disconnected. If you look at some of the coils, and they look like there's a different color, there could be one causing a misfire. Any of the plug wires. See if any of those are loose. Obviously, don't do this while the engine is running and stuff. And then any of the vacuum lines, see if any of those are loose. If you hear a whistle type noise, you're going to want to find where that's coming from, because something could have popped off or been loose. So, double-check all that stuff, all the connectors. Check the snorkel. Make sure nothing is loose here. And even over here, something's loose like that, that needs to be addressed. Someone could have replaced the air filter and just forgot to tighten this down. So, that needs to be tightened down, or even a connector if it just popped off. Or it was never secured properly. It could have been pushed on a little bit, but not locked in place. And then it popped off. Then you can also check the connector themselves. If you look at the connector and you see anything corroded on them, that's not going to make a good contact, and that has to be replaced.

Now, you always want to remember to check your fluid levels. Now, if the engine oil is running low, and the lifters aren't getting pumped up with fluid, that can cause the engine to run rough. Or if the vehicle has variable valve timing, that's going to cause the timing to be off, and the engine is not going to run right. If your transmission fluid is low, then it could cause the vehicle to shift funny. If your vehicle doesn't have any heat, you always want to check the coolant level. If the coolant level is low, there's not going to be enough coolant getting to the heater core, and that's going to cause the vehicle to have no heat. Top off the coolant, and then see where the coolant went. It's probably leaking on the ground somewhere, and that needs to be repaired.

Now, what if your vehicle won't start? It does nothing when you turn the key. A good thing to check is turn your headlights on and see what they do. If the headlights don't come on at all, or the headlights are weak, chances are the batteries either needs to be recharged or replaced. It's always a good idea to check the connections, wiggle test them, make sure they're not loose. And even take the terminals off. And visually looking at the terminal, if you see any corrosion or green in there, that needs to be fixed.

Now, if you have a tire vibration, it's always a good idea to check the lug nut torque, make sure the wheels tight, or even if the wheel has not centered properly when someone put it on. Now, something you don't need a lot of tools anyway to check out is the suspension in the vehicle. You can just grab the wheel with it raised up a little bit, shake it back and forth. See if you feel any movement. If you feel a lot of play, then there could be something that's loose, whether it's a tie rod or even a lower ball joint. And then same up and down. If you feel a lot of up and down movement back and forth, most likely it's a wheel bearing.

So, maybe you notice while you're going down the road and you go over bumps, the vehicle is bouncing around a lot, what you could do is a bounce test. Go on each corner of the vehicle and just shake the vehicle up and down. Then when you let go, the vehicle should stop moving within a bounce and a half about. And if it doesn't stop, it's probably because your struts or your shocks need to be replaced. And if you look at your struts or shocks, and you notice some fluid leaking out, they're going to need to be replaced.

So, if you have a driveline vibration, you're driving down the road and around 45 miles an hour you start to feel a droning in the drivetrain, a lot of vibration, something more than just a tire, it could be the U-joints. If you grab one side of the yoke where the U-joint goes in, and then grab the shaft, and then just rotate back and forth. And if you see any play in there, the U-joint is going to be bad.

Also, the center support bearings for some vehicles have a driveshaft that is supported in the middle. If that rubber bushing is bad, it's going to need to be replaced. If you hear something rattling when you're going over bumps, whether it be in the exhaust system, the suspension, or the driveline, you're going to want to check it out.

So, those are some ways you can check out your vehicle without using any of these tools. I hope you enjoyed this video. If you have, subscribe to our channel. Make sure you ring that bell, turn on all notifications so you don't miss any of our videos.

Thanks for watching. If you want the parts to do it yourself, check out 1aauto.com, the place for DIY auto repair.

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