How to locate an open circuit in a wiring harness

hey guys scanner Danner here I am at Litwin automotive that's right I am NOT at Latour Zotto I am at Litwin automotive in Pittsburgh atop a glass run Road Church view some of you guys might know where I'm at Jim Litwin is my was my service manager when I worked for Pep Boys many many years ago from 96 to 2000 somewhere in that range and then he opened his own garage and the school used to be right behind me down the road in Homestead and I used to come this way on the way home and Jim Litwin was the first garage I ever did mobile diagnostic work for so I am here and we are working on something old-school it's a 1997 I believe Crown Victoria that's had a ton of parts thrown at it let me let you see what I've found so far so I see a new battery coil pack looks like plug wires this coil pack cooling fan the shroud is missing alternator what else an engine computer in the backseat some other kind of model there so as you can see this course had the parts shotgun applied to it and it's a note start that's all I know I haven't begun anything oh wait I take that back one more piece before we begin you see the dash is all apart too the nice thing about my wireless tavares adapter and it has a green LED light on the backside of this that glows very brightly when you plug it in when there's power on the DLC and there is not that is not lit so before we begin I'm going to check these fuses and see if I find one that is blown and use box can't be dead completely can it I mean I got nothing there's one [Music] this one I really have this many dead fuses with the key off it's possible but that's not a good indicator I don't thank you but that's telling me right off the bat some kind of feasible length problem let's see if we have a check engine light now get the key out of my pocket first what did I do with the key in my pocket let's see if we have check engine light or - gauges or any of it I cannot see the check engine light lighter that's right there it is not lighting so check engine lights not lighting guarantee there's no five volt reference on anything let's take a couple more fuses with the key on the keel and these are all powered up except for that 2.5 amp fuse or 25 amp just a weird-looking fuse - and that one's not lit so just one I don't know if I can get into the tabs on this one [Music] yeah there's tabs are way inside there on that so I can't really check that one but visually it's good junk fuse man that's for sure I mean I can't even reach him with that okay well my PLC doesn't have power so connecting the scan tool is not going to help us um let's go into the hood and see what we can find visually is in regards to usable length we could do a real quick 5 hole restack I just don't feel like it's necessary right now I just want to look through some of this stuff I don't know that the power this has the old-school power relay here fuel pump relay I don't know that the power relay was needed for the computer to talk to us I should pull up a diagram I'm going to do that look at some of these maxes fuses let's just do a real quick check on those look guys I'm sucking fuses first are you happy are you happy with me just messin with you sorry about the bright Sun you guys are not going you guys are not gonna see this very easily I'm just rolling through these fuses real quick those are all good okay let's let's pull up a wiring diagram see where this DLC gets power from I know the power relay doesn't provide power to the data link connector so it has me concerned with that I think maybe two separate problems power to the data link connector and then you know why's the computer dead here let's just do a quick here's my cooler temps sensor the thermistor you've got to unplug thermistors when you check for reference voltage all right so you see that ones point point zero two and then this one same thing nothing okay the mid max scale ignore that that was when I checked my battery but no 5 volt rest so the cool part about that is I'm not going to have to worry about crawling underneath second you know crank sensor wires or whatever on the harmonic balancer now this has no 5 volt rest that means the computer is most likely not powered up the chances of it being a shorted reference circuit it is a possibility we'll see as we go here I got to check my main powers to this computer I'm going to grab a wiring diagram I guess one more thing I could do is let's check this power relay real quick again I don't believe the power relay had anything to do with the no comm or the no power to the data link connector and there is green corrosion on this let's just see if we have power here green corrosion and a nice big old spider living in there here let's mess with them cold today did you guys see that I'm going to bring me out in the main binary a spider alive no he is not yeah thank you all right so the power relays here what the EEC power relays here this should be ignition positive fed and not computer-controlled it's grounded I believe to the block so we should have some hot feeds here on this power relay with the sun shining here this isn't gonna help you guys much we got I got nothing here okay now I do have the green and yellow so relays for realized to work guys to function you really need you need to power feeds one load one control and I have is that load or control let me see I do have one power feed on the green with a with a yellow [Music] and that would be this pin so that's the control here's your control side of this relay there's load side so I have control side which in fact list here so much traffic here I don't know if you guys can hear this listen to the relay what I plug it in alright so the relay coil is energized the problem is there's no power here there's a little bit of corrosion on this one terminal nothing that's crazy I don't know if camera is showing that there's a little bit of Krusty's there but there's no load side power to this this power relay so can I continue to troubleshoot this without a wiring diagram I'm trying to think from memory where does the power relay get its load side of the power really get its power from it has to be a fusible link there's maxi fuses so those would take the place of fusible links I think I'm I think I'm going to have to go to the diagram I don't think that I can do this one by memory you just take a quick peek here color was that again see I got those same colors coming from this fuse box I don't know which ones which one is load if I remember the load side of the power relay feeds the control side of the fuel pump relay is kind of a weird setup that's why I remember that so I have a red control side is here load side is here double check it yeah control side load side so the fact that my fuel pump relay control is solid red and this one solid red from the power relay that tells me that that is the Swift side and so that means this yellow and black is is going to be my main power coming in and I expect this yellow black to be yellow black over there at that box that's what I'm thinking I got a main harness here that I can look at that there is a yellow black wire coming out of here yep I see a yellow black do I have power there so I don't even care about the data link connector right now to be honest with you Gus I don't think this will restore that I mean it might because this is a hot all the time circuit see how many yellow blacks I have coming out of this and then I'll get you guys zoomed in on it Oh scared me there's no right now Jim either there's no power to the to the end there's no part of anything so I have no 5 volt reference check engine lights not lit this is a main power issue is what it's looking like my how are we yeah power relays missing power though it's not even there so it's not the box itself um that's why I'm focused over here I remember that one we have you know over here we wrote we've done a ton of those in the past Jimmy if you remember so I believe this yellow black is the feed that feeds that yellow black that I'm missing power on over there so let's get a quick measurement here that should be lit yes all right all right so I just using my little hook tool here that leaves like really tiny tiny marks in that wire also you actually when I'm done a nice thing about this tool is I can touch it down here see the lights lighting or up here in the brass area tough to see in the sunlight test lights lit we're down inside it actually takes a multi meter lead in there too but anyway I believe this yellow black wire is the same yellow black as over there I have to confirm that with a diagram but that means we have a break in that wire from there over to there let's look at the holes that I made in the wire can you see them they were like right I mean I can't even feel myself with my naked eye or like right there then accidentally poked it again right there cold I hear matters and I just poke some holes and some wires what do we do about that real simple liquidate okay I want to hear no more crap just kidding before I pull a diagram I keep saying I'm going to pull the diagram then if they before I pull the diagram what I want to do is a visual here this harness this harness right here looks like crap where's what but looks can be deceiving direction of the harness yeah it definitely goes through here definitely maybe I'm pretty sure that it comes through this main connector here let's do this let's get our test light rigged up to this yellow black wire now you know what a hazard paws is I've run in circles before without the diagram I need a little bit of guide I guess it helped for me to tell you what we're working on right guys what is this thing 4.6 liter 1997 Ford Crown Victoria an old police car it's not a police car but that's what they used all right guys using my old program that I'm up to 2004 with this one I don't have to be connected to the internet for this program I paid about five thousand dollars for about oh man 17 or 18 no probably more like fifteen years ago Ford Crown Vic [Music] what we weren't is a power distribution wiring diagram I think let's just look and see if this see if I was right about the yellow black on the power relay find out here in a minute [Music] Dec fused 30 amp fuel pumps and yellow black yeah all right and where is that IEC fuse that's the one it's in the engine compartment fuse box I checked all the fuses they're all good in there we'll make sure that fuse is there and it is yellow black fuel indicator module is on that circuit hey guys guess what it does feed the data link connector that's cool all right feeds PCM data link connector PCM power relay so we have a break in this wire this is very basic that's where we are let's double check that EEC fuse stupid forward numbers so I need a number and of course they don't give me a number on the wiring diagram so then what we do before I forget guys we have a break okay I'm gonna go check the fuse make sure we have a break somewhere in this circuit they will find the location of that splice might help too but what would I do in the field working at a garage well we're only ten minutes into this so spend your first hour but you know you might sell an additional hour diagnostic time do a wiring harness repair and we'll see how it goes a fuse box is what I want this will be listed under should be electrical and then I can find this usually in the instrument not the instrument panel the the owner's manual is helpful with this stuff so there's my box two three four down and then there's some options police down at the bottom so it should be it should be maxi 14 I'm looking at looking at this and that one right there 14 those two these should be empty at the bottom I think they are yeah you see down here there's this upside down no the relays are here so this this 30 amp right here this is my eec 30 amp fuse from here right it's good so and we're good coming out what I could do you know what the real Ikhwan electrical tape this but I want to try let me just make sure that I'm on the right wire here this yellow black and that's lit when I pull this fuse that light should go out yep alright so that is the correct circuit where is it broken that harness runs down this way to the fun of the vehicle I wonder if this had some have any work in the front if it get damaged at all yeah I was thinking it went that way but it looks like this main harness it splits one half of it goes over this way into this fender and the other half comes down that way I've all that for a second back to the wiring diagram real quick s 151 engine compartment harness near breakout to right headlamp would be a nice place to do a test fuel indicator module let's see if that guy's got power to it I wonder if that's that other module that God changed where does that go what is this hang in here vehicle protection system [Applause] okay I'm gonna try a tool not sure that gonna work out for us but let's give it a shot so other than a visual inspection which we can still do I have a tool I've only used it's like one other time I'm not totally sold on it yet but it's this it's an open circuit short circuit finder and let's see if we can use this to help us this is a tool that I have used literally one other time so you guys will have to bear with me as far as my lack of knowledge here with using it the tool that beeps at us I've never even opened this package I used someone's I thought it was mine nice they give us a DVD the problem is I just need a quick reference right now on what I'm doing here I don't even know how to connect this thing come on power probe the quick manual for me right now is really important okay I'm not loading this DVD right now we have to try to figure out how to use this tool I don't know that I even will I might go back to a visual inspection there's some some of you guys have been using using one I've seen it online on my website on my forum a frequency generator which is basically what this tool does and emits a frequency in a circuit and use a tool to find the open some of you guys mentioned using something from Harbor Freight that you really liked so we got juice and then what do we put this there's two ways to hold it yeah we've been short wiring harness probe so yeah they're showing a picture of it so I believe this green line we actually what I want to inject this frequency is coming out of this green line so I want to get it into this relay where it's dead and to do that what I can use is this a doctor that's cool and let's just put it in there if you have to make sure the circuits dead so I don't want to go a pretty short I don't want to go on the few side because it's hot over there but it's dead over here let's completely isolate this circuit the relay out of the picture and we'll put our tool right there what's that why is that beeping at me it says short or grounded circuit why so in other words whatever else is connected to that circuit is providing a path that's that's what that means it says short or grounded right now and I think the issue with that is can I still use can I still use my question is this and some of you guys could probably answer this question sorry for the beeping what I am questioning is because this is telling me that the circuits showing a short can I still use it for open circuit test it's not shorted this is misleading because there are other feeds for this circuit that fuel pump module the pyro relay feed and then the DLC let me look at the diagram again real quick it looked at so basically what I've done is I've taken taken the not from the fuse side but I've taken from the the PCM power really this is removed and I'm injecting this frequency here very very possibly this tool is showing me that it is shorted because the PCM is still plugged in and we're getting a ground path through the PCM it's not an issue it's not sorted so my question with the tool then it could also be the fuel indicator module as well my question with the tool is can I still use it with that light on just experimenting with the tool here for a minute [Applause] see that's being tripped by anything that's battery said is it I apologize guys I I should know my toll before I start using it yeah I don't know why it would be beeping on the main power feed coming in I think that it should be I need a PDF on this tool I mean it only has a power and a sensitivity lock there is no other settings see if I could follow this harness underneath I'll take you guys with me when I can okay okay without it beeping and with the solid life I don't know why it would be beeping on the on the wiring that comes from the battery I don't think it should be but when I go to the alternator battery wire which is hot it doesn't beep so I think I'm using the tool right now you see it beeps on my green wire beeps on the harness come over this way nothing go down this way cool is it in this harness these brake eyes are really rocky - yeah no reaction there so that harness then probably splits you know I'm reading it here splits and goes one goes this way one goes that way so that means it's not here that it goes under the fender or in defended and I read it through here yes I can call I think I like tool you show a little closer view here no don't shut off I had it working right okay and the harness it splits it comes out of the box you see it comes this way and it goes down here and then when I go toward the engine compartment what I was thinking it was in here it's not right here where that split is it doesn't go that way but then does here I don't know that the lights going to show this but that harness runs into the fender and then that's where I got this this reading watch test follow this harness and then here my issue here is I may have desensitized this too much tried on that setting still have a reading here and it comes off you [Music] [Music] make sure I'm not getting interference here all right about this for a second I'm pretty sure that harness runs here so that harness runs along here it's definitely in going into that harness so where's my breakout right over here right underneath the battery maybe I really can't get this pool in there very well let me look under the passenger side this harness right here I'm pretty sure we're good up to that point I got this elbow right here that goes up top so what that suggesting is it's in that area but man I don't see damage looking for a vehicle say accident I apologize if I wasn't using this tool right I really need to watch the DVD I just I don't see damage in main harnesses like this unless the vehicle was in some kind of an accident and that's what I'm looking for evidence of an accident but I don't see it these bolts everything looks good you usually find a vehicle that has been messed with you'll see that all the bolt holes will not align correctly on the fenders and stuff I need to look underneath sorry guys the cameras not coming with me for a minute yeah it's right there that's right there right in the main harness I am shocked I'm shocked now can I get you under I got to get a jack and jack stands there's no way you guys are going to see that where we are out here so let me pause this and I'll be back in a minute all right guys we're going inside I can't do this on the ground out here hey let's give Felix Horsham crap off because he never rocks cars for me alright so what I found guys is with this tool plugged in I'm going to redo this test again it did work we found the location and I'll I'll show you I just want to make sure that I'm representing this tool properly I have an open circuit now here and what was happening was with my scan tool plugged in it was pulling that to indicating a short let's see what this does oh yeah that'll be better I think we were fighting that maybe a little bit watch what happens when I plug my my scan tool in to the DLC so I'm just plugging in the wireless VCI that's all and Boyce it a lot quieter in here isn't it watch what it does it's actually probably the bulbs circuit of this more than anything I can't get in this car I forgot about your racks can't open the damn door can't reach it ok I'm not showing it to you I cannot reach the DLC I cannot open the door but just like we said you got other stuff on the circuit that still plugged in it can show you a sort even though it is not so let's redo this test again different tone with an open circuit ok that's cool so it makes that sound on the main harness power and ground coming in there's my open circuit one follow the splice now it's not sensitive enough to even pick it up okay you know what I don't know why that is not working for me but doesn't matter it was actually functional when I have my scan tool connected did I have the key on before the whole I did have the key on interesting the fact that I can't read this harness and I know it's good up there it's weird all right you know what let's raise it and yeah let's go up all right so this is in the the passenger wheel well and so the tool was giving me a little bit of grief and I still have a learning curve with it but this main harness is where my beeping had stopped and I opened it up in the parking lot I saw some green corrosion I'll get my hand out of the way in a second you see it right right there there it is Jimmy and it's only one wire it's my yellow and black one - yep so we use a heat a heat shrink plug connector for that right here guys right there and that is my yellow black wire look for any other damaged ones in that area you know something pinched that harness at one point in time Jimmy it had to us I mean that's not typical and that was inside that was inside the conduit there was no evidence of damage there at all I don't know that I would have found I mean I would have done inspections but you guys can see how nice the tool is with a frequency meter I again I learning her with it I was not using the tool properly and my scan tool being connected to it had a factor in there too but any other broken wires nope maybe maybe this one huh just the one wire a-b - nope the screen on the outside there it is right there man I can't believe how many parts he put in this car for that I was freaking ridiculous I was unbelievable so I should be getting signals here no not okay I am so I have a signal coming in from this side this is where I'm injecting the frequency from the power relay there just got to be a way to make this a little bit more sensitive because I should be able to read that through the harness and I'm not but I was able to when my scan tool was connected that was showing a sort so learning curve on this tool guys a promise that I'll do my homework next time I use it so this is driver side now and it reads on the back at the passenger side but this harness runs down here and I should be able to read that I was reading reading it in the inner fender before why okay I need to pause this for a minute all right guys last thing I'm going to do is talk about a tool and use the tool if I can't make it work right and I can the sensitivity of the tool when I have my scan tool connected showing a short-circuit actually helped me find this open so I did find it using the toller's know now but let me show you what you do with an open circuit right now I have the tool still connected to the the power relay on the load side and what you do with the transmitter turned on powered up power this guy up and then you start you know you hold it close to it and then you each level that I hold this away I can lock it so once it happens if I hit the lock button now what happens is it ignores everything else until I get to that level and what I want to make it the most sensitive is turn it on move to the tool move it as far away as you can or it's beeping hit the lock button and now watch what happens move it away come towards it okay so it from there in right I have it as sensitive as it will get right now and I'm at the harness where it comes around I couldn't can you move this ladder for me for a second Jimmy when I had this tool set for a short whenever the data link connector was connected I was able to pick up the harness in this I just shut off on me to see that is something I don't like because I have the sensitivity set now I got to crawl back up that's not cool at all I don't know if it's still set to that that's bull no I'm not a fan of this tool I need to get me a better one for an open circuit this is ridiculous so gotta reset it I need hurry now doesn't shut off on me but I have the you see the wire here right so I'm able to read that the problem is that is the harness okay problem is if I move it anywhere else on this it won't read it it will not read with it very little insulation around that it's just not sensitive enough I have it set to the maximum sensitivity so for whatever reason it was able to detect the short circuit with the DLC plugged in but this open circuit test I just kind of I guess I got lucky I got lucky in that my data link connector was plugged in and it was allowing a complete circuit it was a shorted circuit test and it would actually allow me to follow the harness so I guys we got walkie with a pool I need to use it more before I condemn it you see our open wire let's fix it get done with this car get out of the camera's way I get the whole car on fire with this thing that's not what i Iike we go this is the um this has the sealant in it - Jimmy yeah so it has like once you heat it it has a almost like an epoxy tit melt inside of it all right let's get this Hornet back in place it won't start yet because I still got the arm I still have the power relay out so let's get this out of here plug this back in and what else do I have permit if anything now we should be good guys give it a shot I never even cranked it so hard the fuel sweet yes it is I mean I mean he changed coils and wires and computer and crank sensor and modules and holy crap man just a simple voltage measurements all you needed I mean we seriously Jimmy had 10 minutes into this I knew where my problem was the rest of this we've been good farting around with this tool and got a little bit lucky finding that open where we did but open circuit really I'm really disappointed in the open circuit test of this tool the shorted circuit worked really well and the fact that my doddling connector was providing a ground on that circuit allow the tool to work in a way that it's frequencies were different and I was able to find it but I'm really really disappointed in the open circuit part of it but I was able to find that problem using using the tool again there's a learning curve for me but I think the open circuit test leaves a little bit to be desired it even says in the owner's manual how weak the signal is for the open circuit test so but it's hard to hard to knock the tool when the tools put me right where my problem was I guess the only issue that I'm thinking about in the future with an open circuit test is you know what make the circuit sorted to be able to find it at the ground one end of the open much sore again learning curve sorry I didn't crank this thing over for you guys to hear that it doesn't start it wasn't really necessary there were no five volt reference to anything check engine light wasn't lighting but we're done so pretty simple one well the only struggle we had guys with and I'll update you guys more on on the tool and I use it some more I apologize for for that part special thanks to my friend Jim Litwin for letting me come here and film this and for more information on what I do go to my website it is scanner Danner comm and I also want to remind you guys about scanner dander premium which is right here on YouTube it's a paid YouTube channel where I bring you into my classroom at Roseville Technical College and I can train you online so make sure that you click on the link here and check that out too thanks guys I'll see you next time

Channel: ScannerDanner

Views: 710,789

Rating: 4.7533746 out of 5

Keywords: engine performance diagnostics, technician training, auto technician training, rosedale tech, auto repair, ASE L1, how-to, DIY auto repair, no 5 volt reference, no power to ECM, no check engine light, no start, no spark, no injector pulse, how to find an open wire, open circuit, high resistance, PowerProbe, ECT2000, ECT3000

Id: w9PKJrK4Fbs

Length: 50min 25sec (3025 seconds)

Published: Sun Aug 13 2017