Today we’re gonna be diagnosing a short or potential short. The car will not start after a few days so it could be a few things

it could be an alternator that’s going bad . it could be a short or could be a bad battery this article is going to show you how to test to see where if you have a short and where your short is

so we’re gonna pop the hood , get to the battery . First thing you’re gonna do is get to the battery and on PT Cruisers , it’s right below the air filter so there’s these two tabs on the side

You just pop them open and then you can lift this and your battery is right there. I’m also gonna take off this so you just use a flathead screwdriver and unscrew this and then this whole piece will come off with our air filter box off .

we have access to the battery and so locate the positive and the negative. what we’re gonna do is we need a 10 millimeter wrench, we’re gonna loosen the negative side

You could either loosen the negative or the positive .I prefer the negative because if when you’re doing this test if you grind out the negative , you’re grounding out a ground

it’s not a big deal if your ground up the positive . your grounding out where the power is coming from so that could create a short and blow something

so we take off our negative before we start testing the connections. we want to make sure that we sand it a little bit of sandpaper. we want to send the terminal , the post and the lead and you’re gonna get inside

I can’t really do it with one hand but you get the idea so sand inside here until it’s nice and sanded and there’s a really good connection and then you don’t want these two touching

so keep them separated and you don’t want this touching your ground either. we have this multimeter and what it does is it gives you DC volt . it gives you your ohms which is continuity AC volts DC amps and a battery test for a load, we’re going to want to test the battery first

To make sure it’s good so make sure your connections on the right one see it’s this battery grounds there , I’m going to use twenty volts as our base so now to test the battery very simple, you just touch the two sides negative to negative positive

My case is 12.4 it should be twelve point six or higher so that’s good I’ve been messing around with the battery a little bit so it’s it’s down a little bit and there’s obviously a problem

so it’s it’s down a little bit but that’s charged enough where we could do this test

so now what we’re going to do is go to our amps DC amps and if we do that we have to put it to the DC amp side which on most multimeters you need to move this

so now it’s on amps now we’re going to take our disconnected negative terminal and bridge the gap with these. we’re just connecting and you could see right away that says seven point eight six almost eight and load

Now what we’re gonna do is come over to the fuse box and we’re going to start disconnecting fuses one by one . Some cars, it’s underneath the steering wheel, what you’re gonna do is gonna disconnect the fuse

I just use a little needlenose and you just pull it straight out. Your fuse is disconnected. That’s one fuse you can look in your manual or in this case, the fuse was a 25 amp HD lamp switch so a headlight lamp switch and that’s the right one . that’s in position one

so if there’s a problem with their headlight lamps and that’s causing the short you would notice that there would be a drop in voltage

There’s still a parasitic draw of close to 10 amps it’s 9 9 amps and so we’re gonna just pull fuse by fuse until we see that drop down to as close to zero as possible and it should be in the decimal places and once that goes down to zero that means we found the correct fuse

that’s connected to something could be a radio could be a headlight could be and whatever the fuses are connected to and then we could diagnose that and that’s where our short is

and just as a reminder one thing you want to make sure is there’s parasitic draw all the time especially like when your doors open your dome lights and stuff are on when your glovebox is open that light is on sometimes depending on your hood

but if your hood has a light and your hoods up, that’s on so you want to disconnect the light on the hood. You want to close all your doors and then you want to check your parasitic load of 9 amps in this case

and when you’re pulling the fuses ,you want to try to keep the door closed so a good thing is you could pull the fuses with the door with the window open and the door closed

the other thing to remind you is that most cars have a fuse box underneath or in the engine compartment and the label fuses and I’m gonna pull fuses one by one and have somebody tell me if this changes as I pull nothing change , went down to 1.59 a fuse number eight which I will show you

there’s still a decent amount of draw but we’ll figure that out later but the big thing is fuse number eight which is for the fog lights ends up being the one that caused a huge draw

so that’s what we’re gonna look up next and see if we could find why it’s causing the draw . I put the fog light fuse back in because the fog light should be off , everything’s in the off position

I went back up and notice the fog lights are on so there’s your draw sometimes. it’s not that easy in my pickup truck. it was the radio that was broken and everything worked fine

the battery would just die after two days of sittings so the problem is this fog light now that you have the problem area figured out

you could go and diagnose the fog lights or your radio or whatever your problem ends up being but that’s how you test for a parasitic draw hopefully this article has helped you guys and if you have any comments or tips or any ideas a lot of times you guys give me good ideas for stuff that I didn’t include.


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