How to Test Circuit Amps.

Adam Mechanic

How to test a car electrical circuit for current/amp draw. This may help find why fuses are blowing or batteries are draining. Please follow and like for more content.

Transcript

00:00Hi everyone just a quick video on how to test for the current draw on any car circuit so

00:05obviously we have fuse panel with lots of different size fuses in there and depending

00:10on the ampage obviously that'll be what the circuits are designed to run up to as time

00:14goes on our motors become less efficient and they have more resistance obviously the current

00:18needed to drive that motor will increase to the point where it may start blowing fuses if the if

00:25the resistance in the motor or the bulb or whatever circuit it is becomes too high so how can we test

00:30the circuit for how much amperage it is well first one the easiest piece of equipment i've got here

00:35is called the fuse buddy or a car current tester as you can see on it and it will do up to 30 amps

00:40it's the easiest piece of equipment to use in the world you've got two different types of spade fuse

00:45that you can use on it the big one and the little one and then what all we're going to do is put the

00:49original fuse into here they're not a lot of money these about 15 pounds this particular one will do

00:54up to 30 amps which is enough for more circuits apart from the main ignition ones so what i'm

00:59going to do is take off this fuse cover i've already located the one that's uh for the pop-up

01:04headlights so that's one i'm going to test for you now so i'll remove that one and all i'll be doing

01:09is putting the fuse into here to protect the circuit and effectively this fuse but is going to create an

01:14extra loop on the circuit so rather than having to go into the door or into a panel to get to that

01:19circuit and put a multimeter into it you can just simply put this in the fuse panel

01:24and get a reading of that circuit energized so i'm just going to plug that into the

01:28uh port where that fuse was into here and plug it in and then what i'm going to do is take you guys

01:35with me i'm going to put that up there to the windscreen and then what we'll do is we'll go

01:39around turn the ignition on um and we'll see what draw we get in here so the fuse itself is a 30 it

01:49should be nowhere near that if the circuit's healthy so uh what have we got down here at the moment we've

01:53got zero zero dc let's turn it the way around so it's easier and what i'm going to do is turn the

01:58pop-up lights on and we'll see exactly what uh draw we're getting so ignition on pop-up headlights up

02:076.8 so you can see the 6.8 amps it took it's a 30 amp circuit

02:14um so there's plenty of margin there the motors are not in too bad condition on this one

02:18uh if you were getting somewhere up near the uh the maximum because i was getting something in the

02:2220 amp range uh i'd assume that the motor's got high degradation it's taking a lot of current to

02:28to turn that motor due to rust and internal faults and i'd be looking to change the motor but in this

02:33case uh plenty of margin there it's a good test to do because obviously i say some fuses do multiple

02:39circuits so just because it's doing the pop-up lights on this car it might also be running heaters

02:43stereos um wipers anything else so that some fuses use multiple circuits by doing this test on each of

02:50the ones that the fuse covers you'll be able to diagnose which circuits causing your fuse to blow

02:55hope that makes sense and we'll see you in the next one

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