Where’s the Fail? How-to Find an Open Circuit on a Car 3 Different Ways

published on August 3, 2020

Previously on Brian's mobile 100 on this cross track the horn doesn't work so we need to see if the ground wire in here is making contact and you just push like that horn wire does not give anything anywhere we've already run it through all of these and you see we've got

Everything hooked up again this is the sound we're looking for and you can see we've got continuity on that pin blowing wiggle and we just click it into place a lot easier to put this on once that thing's going you know how it's supposed

To and that's it we are fixed Brian's mobile one as you saw in the previous video we diagnosed the Clark spring or the roll connector it had an open circuit for the horn signal wire I wanted to do a new series that is a

Throwback to some of my older popular diagnostic videos where I tear down a failed part and show exactly what failed inside of it so in this video I'm going to share with you a bunch of cool stuff there we go you see the uptick right

There that can take you from a level of swapping off sticks to a level of diagnostics and not much time there's three different diagnostic skills that we're gonna use in this and then you can use these like I say if you're gonna

Diagnose a part in specific you can go back in and fix it and correct it manufacturers if you're watching this and hear from Subaru you can see that there was a material failure in this one you know strength of materials was weak

In one particular spot so anyway we don't learn something cool three different techniques I'm going to talk about is the wiggle test if you're dealing with an electrical problem and there's a length of wire involved a

Wiggle test can help you to be able to narrow it down obviously just wiggling or hello you know isn't gonna help but using power probe and some other things I'll leave a link in the description for that you don't have to spend a lot of

Money in order to diagnose things mandy concepción that guy is amazing at creating his own tools for doing diagnostics like this but a good shortcut I would say is to get the power probe because it makes it so convenient

And it's thing that you can use on a regular basis so wiggle test with a power probe we're going to do that we're also going to use the Fox and Hound tool I'll leave a link in the description for that

Companies like cable companies internet cables all that kind of stuff for diagnosis in the Fox and Hound tool because you've got lots of wires in a little bundle and maybe gets hit with a staple or gets bent like a paper clip

And gets snapped and then another technique that I use is back probing using t pins you want to use T pins sparingly it's a last resort to really narrow things down now this part was failed and so I didn't mind

Poking a bunch of holes in it forsaking the video and then we go to a microscope in order to see exactly what happened learning from this makes you better at diagnosing things makes you better at diagnosing parts cars and you know it's

Not just clock Springs so hopefully get some cool takeaways be sure to leave a comment below what part of the video you like best or learn from or whatever I love having that feedback these videos are not easy to make sometimes but I

Love getting the feedback I want to do this for you guys so let me know what you like and we'll do it some more let's get to it alright so in a previous video we showed when this lines up that we're correcting in terms of clocking

Indexing whatever you call a clock spring they call a clock spring because a lot of clocks used to run not on batteries but on Springs there'd be weights and Springs and all kinds of unique rank the key and it would take a

Spiral type spring and wind it tighter and tighter and then as an unwound it would move the mechanisms internal workings of the clock right well this clock spring or what they call a roll connector there's a roll of wire or wire

Ribbon matter of fact inside there so let's get into it we determined that this pin right here is for the horn directly the one that goes to the airbag unit and then it corresponds with not the top left but just one over to the

Right from that this one right here so we need to trace that wire and figure out where's the fail first thing you want to do to get into these is decide which way you want to go you want to take out the middle or the front plate

Because there's connections both ways let's pop this off I've already addressed this a little bit what you can do you can use the T pins like what you use to pin frogs and what down you can stick those in you know

They don't tend to damage anything too bad and they get things to come apart so that's out and without out you can actually open this up because they're holding each other like a sandwich so when you go

Inside you can see there's that so how many buttons how many things do we have you can count let's see so the fun thing about this is says five turns on this and if you don't have something to hold it and you just have a clock spring and

An answer to this question that was posed in the last video how many what would happen if you put this in neuron what if it was in this position and not this position without showing so it says five turns so if we're in the middle of

Five there's two point five this way and two point five this way or this direction in this direction so if we go around once twice three times a lady so you get to half turn and there's tension there it won't go beyond that so there's

Two and a half that way so there's half one two and we should line up again and we do so let's go the other way we go once twice three times we go a little bit further so it's actually five point two five turns so anyway would come back

Up to here once twice and it should line up again so what's happening with that ribbon inside and what happens if you have it in the wrong position and you go to do a u-turn you get your wheel all the way cranked and tell your control

Arm and steering knuckle and everything limit out on each other so that's as far as you can turn to stop it this runs out of wire before that happens it Yanks it out the ends and we're going to show you that right now so we're gonna go all the

Way to one side tell us all the way to the right and when we do that we can see that there's no more wire on the spool it's all somewhere else so where is it let's give ourselves a little bit of slack so it goes into there so the pins

All come here so keep it keep track going through here so that ribbon matches through that so you would tear that ribbon if you're turning right and you ran out of it because in the wrong position but you see how it wraps on the

Outside using these pulleys so these pulleys ride on the ribbon here and they write on it on the outside so I'm going to tighten that up and let's go all the way the other way let's see what happens so I'm all the way the other way the the

525 I've gone 2 to 5 past the 5 and then when we look at it it's all on here and there's very little to no ribbon anywhere else in there it just goes to this right here where we find our pins connecting into this block so it would

Be ripping out the other way if we'd been turning left and we already had this turned to the left a little bit say 1 turn or two turns and we turned left it would rip it out of this end so depending which way you're turning it

Would either rip out on the inside or the outside connection so that said and having looked at that now that works and there's the two orange ones and then these are also wheels these also spin as you see there you have a gateway here

Gateway here and then it just either wraps up on this or not and so in this carriage rolls clockwise it just takes the ribbon and rolls it on the outside as it goes counterclockwise it rolls it up on this side as you can see that

There's a little bit of buffing and chafing here that's where there wasn't lubricant or there's contamination dirt looks like just dirt as it's coming off so that can contribute to the fail if it's worn through and broken wire in the

Middle of it but we're not so sure that so we're gonna pop this open the rest of the way through these connectors and check that out I just wanted to do it that one way first you get a flat head screwdriver and this will help for

Getting in the crack and spreading it open we could just ravage the thing the trouble with that I find is that it we could cause more fail than what we're trying to find so I'm gonna be careful maybe a little bit surgical because I

Want to see exactly where this failed why did the horn thing fail like we guess right now go ahead and guess in the comments where you think it failed it fell on this side or did it fail on this side

you see we've got a hard right angle Bend here have another hard reading we'll been there we have a connection here and then it turns to go into this so we'll set this aside for now this is

The backside case this can come through we'll set that aside that's where our little retaining thing was and it doesn't look like it holds anything else together at all if we wanted to take it out technically we should have to push

Something here and then from there we should be able to pop that out let's compare the two of them side-by-side and you can see it doesn't have to be and then you don't have to snap it off if you ain't get out as long as this

Doesn't break you're okay that's good to know peace of mind so we'll set all of these things aside we'll unwrap all of this and we can see that one is longer than the other one because it's got to go a little further around so now is the

Time to hook up some wires and see if we can find where's the fail we're there okay so we know that it's in this top tier ribbon so we've just eliminated if I have

I went a little I'm gonna put this back on so far we haven't met anything that's glued or riveted or some other kind of thing that makes it hard to get undone I know that separates without causing a fill we want to find the fill as it was

In its natural state not it's something they got broken or taking it apart right we're gonna get rid of these we know we're not going to use I already bought a new one someone ribbon controls one firing

Mechanism and then other rhythm controls the other one so we have redundancy just like you have in aviation so if you had one bad plug or one baguette squib you still have another one so the one that the horn is on is the orange one that's

Got the blue and the yellow wire on it let's see if we can get this tape off and separate the two see we got this one totally separated so it goes from being the very end wire and ribbon on this end and to being this one and which end

Failed we don't know yet well we can do is we can ditch this because all of our wiggle testing didn't speed anything up and there's a time and a place to abort mission on that so then we're gonna take this and hook it up to one end and see

Where we get tone okay this is the steering wheel end that gets most of the movement I would imagine I got this all set up so that I could film it and present it simply and I broke it these teeny tiny little connections here broke

One of them that goes to this line so I can't use the Fox and Hound because I can't send ground signal down this side and the other to be able to get that sharp contrast where the break is so it's just the second one right here and

It is torn so I was just probing along like an alien and scratching these to see if I had signal to pick up and I scratched a little bit too hard and wound up breaking this right here so then I had to solder it see this is not

Got signaled the other neighbor doesn't have signal this one so that's pretty good bullseye in a perfect world this ribbon for the clock spring would be laid out flat so that we could probe it and check it so the first

Thing you do is a wiggle test so I like to set up my wiggle test with the power probe yes I use a ribbon cable to go to the end just like we did in the other video and then I connect my probe on to there so basically it's like I'm probing

Both ends with hands-free so I have clamps on both ends so doing that if I were to wiggle this and wiggle the connectors or whatever say I wiggle here and all of a sudden I get tone I'd know that the problems here if I were to

Wiggle the other side same story but if I were to find something suspect and lace up then over the top of it to bridge the gap I know the problems here then I'd be able to find that the problems right there if I want to find

That same problem with a tone generator let me show you how I do it you set it to tone and then I've got two wires this one is the one that sends the signal it's like a radio signal that goes through the wire that can be

Detected by this receiver so I'm gonna hook this up to this side and then I'm gonna hook the ground to this side and what that does is it makes it so that the whole everything doesn't become a signal let me show you what I mean so

We're gonna disconnect this briefly and we're gonna turn this on and when we get close to anything it rings but it all rings that's the problem we want to narrow it down to just that one wire so we hook up the ground and from there

you kind of draw actually it's all connected again from messing around with the pin you have to cause a break again there we go good clean break I think this is too

Close to fyssas close because you can use the back end of this see how the back end also acts as an antenna so if it's too close it'll interfere there we go see it just kind of drop off let's get a little stronger as I get closer to

My ground you see the uptick right there so that's the right way to use a tone generator the wrong way is to be like this and to be dragging the whole thing over your wires you got to use the ground wire not always but if there's

Anything that's touching or shorts to ground or whatever then this will make a big difference this detects open circuits are broken wires really well but you have to make sure that you using it properly so we know it's like right

There we either found this really quick if I'd have been using it properly the first time I wasn't so I had to skip this step and go back to the power probe so wiggle test was the first one Fox and Hound was the second one and then just

Like we use the wiggle test before we hook this back up and then the other ones at E pin so then we take the T pin and we just verify that we are connected on this side oh that came off how embarrassing okay so that's connected

This has good tone so we just follow along and just poke into the ribbon that we know it should be and then when we quit getting signal well know that that's where the problem is there's no signal there back up a little bit so

Then we could find it that way the downside of doing this is i zoom in I'll show you you can cause a weakness and you can cause a potential break you know for where it moves these broke I think this

Was probably for manufacturing the strand inside had a flaw to it or something but even the plastic on that outside failed which makes me think maybe there's a device that grabs onto this you know to manhandle it like a

Robot grabs it and does some kind of process at this point and then nothing doesn't matter how hard I stab it nothing this is kind of a last resort and if you can you should put some kind of a sealant over it so that it doesn't

Cause a failure after all whatever bit this here was probably about the same or less than what this t-pin did so here's all the carnage here's the tools of the trade and here's a microscope looking at the damage that we have so this is the

Ribbon and on the ribbon you can see there's all this I used a dry erase marker to mark where on the ribbon it was and then I tried to wipe it off and what that did is it really filled in the gap where you could

See where the breaks were so I have continuity all the way through here all of these pin holes also got dry erase marker in them that's everywhere that I probed it using a needle those are needle pricks so here's the

Microscope we'll get that out of the way this is with something in it without it you don't even see that at all it looked the same all the way around so there you go now you know how to properly use the fox and hound tool the wiggle test using

The power probe and the power probe in order to do teeth and stuff having a little jumper cable like this is really nice having T pins is really nice I've got links in the description for all that stuff if I didn't have these ribbon

Cables then I wouldn't be able to get onto these tiny things so if you have a breadboard or some test circuit say you're doing some Arduino work or whatever that's where you find these and those can actually be awesome you can

Come up with all kinds of cool workarounds and diagnostic tools using those kind of things as you can see they've got pins on one side and then they've got the corresponding part on the other side and there's there's flat

Spade connector one so you can get there's all kinds of cool stuff out there it's a great time to be alive it's a great time to be a mechanic we've got so many cool advantages over what has been in the past now bear in mind when

I'm sending the tones through this you could use a speaker you know like a radio speaker to get a signal or something you could use a light bulb just anything that your five senses can pick up that can respond to stuff you

Can do it but for this the tone works great it's like having a speaker and there's a little light on it so it's like having both I kind of picked this up on my own I think the internet installer guy had one and so I went and

Found it on Amazon but I was like dude be able to trace wires like that heck yeah I spent so much time on my assumption for educated guess hypothesis whatever that it was going to be in one of the

Ends of that ribbon cable and it was in the middle so whereas all my attention was being spent on the outside that when I was going across with the tone generator was gradually fading off when I got halfway I didn't see anything

Halfway because those little cracks were so small till I rubbed it with a dry erase marker it made it a lot easier to sit like well duh there it is but because it had smudges all over the cable and a smudge on that location I

Missed it when you're doing the diagnosis it's important to be able to let go you know it's like if you're in a if you could you have a bad car let it go give you I stay short to have

A bad car problem lemon car right so if you can let go of your assumptions or let go of your hypothesis and be humble enough to pursue something else again save you time frustration and all that kind of stuff anyway I'm excited about

This series I think I'm going to learn as much more than you guys are gonna learn from it but what a cool thing in the manufacturers Subaru can learn from this because now they know where's the fail what happened and they've got a

Microscope view of it so I'm really excited about this but making videos is fun again because the how-to is fun because they empower people but so much of the time I never hear back from you all you get onto YouTube you watch the

Video to the part where you get what you and I've done it – yeah the part where you know what you're looking for BAM you balance your out and this way I'm helping people but I'm helping people to learn principles or learn cool

Stuff about how things work and then that itself can teach people how to fix cars basically so I'm gonna focus on the words that fail because that's where it's easier for me to just get through the job get down to the failure in that

Early part of the film then turns out apart that's funner it's easier it applies to more people and I think this ought to be a lot of fun I'll still do how-to videos but I'm getting tired out it is so much competition for the how-to

Videos – so this should be good keeping it fresh thanks for watching Cheers enjoy the be fate

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