Hey there, viewers welcome back to the self made knowledge channel. Here's our 2008 chevrolet, it's actually a gmc, it's a sierra! It's a 1500! It's just not as fun to say: it's got the big 5.3 flexi in it, and the customer complaint is there's no turning signals on the left side of the vehicle unless he puts a 30 amp fuse in the hole which case he's got a rear. Turning signal. But nothing on the front and then ultimately it fries that one had another shop.

They chucked some parts at it changed a few things. I think some multi-function switches and stuff, like that they put a fuse box in it and then got to the point where the truck wouldn't even run so then they put the other fuse box back in it and put stuff back how it was. I asked them if they could just put it back as close to stock as it was when they received it, and then we'll take a look at it. So here we are, they put the fuse box back in it left the used one in there.

I think everything else works as it does. At least the truck runs now uh. I did verify when he brought it in the 15 amp fuse was put back in. Of course, it was blown.

I put a 15 amp circuit breaker in there, so we don't keep blowing it and turn the turn sign on and indeed the rear. One does seem to work. The upper and lower portion of the bulb uh no blinking in the front, but as it's blinking the one in the back before it trips, the breaker, you do see it dimming the lights down, so there is a pretty high current draw at this point. I printed this out some wire diagrams and we have to come up with a plan of attack.

I've got the battery maintainer on it and we're going to go from there. Let's see we're gon na have a look at this diagram. Now i think we're just gon na pay most attention to these front lights for the time being until something you know dictates otherwise uh, so we got the left lower and the left upper now these are on the front. I believe yes, we're on the front controls.

Oddly enough in these diagrams, they do not show the fuse that feeds this body module that runs. You know these turn signals um. I guess i could show you that i guess it's probably neither here or there, but just trust me. There is a fuse that feeds the body module that when it blows and it's labeled left turn break, i believe so being the fact that when we look at the rear lights, which i've got them up here, so these are left, stop tail turn.

You know left lower, left upper, they both function uh until the fuse blows, but the front there's nothing. So i assume our short is probably in the front. We need to come up with a plan of attack. I assume that you know this wire out of the body.

Control module comes out, and it's going to be. I think this must be some different rpo codes, depending on what it has uh, which way this thing goes and which connectors it goes to in the underhood fuse box, which are just jumpers. It looks like it comes in on connector, you know x4 pin a1 and out on x1a2. They look just like their jumpers or splices.

So it's kind of odd that it runs it through that fuse box and then out to this x100 connector, which is probably the headlight connector and then right to the headlight. So i think what i would be inclined to do simply because on this truck i think i would rather go to this connector here and unplug it and see if our draw goes away, but we need to get a measurable draw first uh just out of curiosity. Typically, taking the headlight out of these chevys is a difficult task, but apparently he told me he already broke the the bottom bolt, so you just have to take the top ones out. So we're going to see, if that's true and go that route just because it's simple get us to that circuit and see what we can do from there.

Nice part was. The upper plastic piece here is busted in half too smells a little like frustration, so we're gon na see if this thing does just wiggle out of here, which that would be fantastic. He said it was all busted on the bottom. You get a light.

Usually you have to pull all this stuff off on these chevys. It's real convenient, oh yeah, she's broke all right. Both tabs are busted off the bottom and the side of the headlights busted out um. I guess, instead of making a mountain out of a molehill here, i can reach this connector just visual inspection here i don't see anything right off, but i'm just going to unplug the turn signal to this left front light and then we're just going to kind of Pull this connector up, i'm going to substitute a known good bulb across this connector.

This connector looks appears to be in good condition. Um, i'm sure the ground is probably the black wire i'm going to verify that the blue wire with the white trace is going to be our turn signal wire and then we're just going to like to say we're going to substitute a bulb here. I'm going to grab one of the toolbox just a 194, something light really low. Current we'll stick this little guy in there and then we're going to kick the four ways down and see what happens some people might say.

You know why. Why are we going here? First, well simply in this, in this instance, it's because it's easy, uh somebody's already been here and busted everything if they hadn't been um. I'd have to look at the diagram uh at that point, i'd probably the bcm would be the easiest thing to get to. I would go there and i would verify our current draw is in the front circuit and not the rear circuit, which we may still have to end up.

Doing i just figured this is convenience. Let's, let's get after it. Let me find out. I just want to find out furniture.

I know that one is the turn. I'm pretty sure this one is the ground couldn't be wrong, it doesn't matter. If i am, let's kick on four ways all right, my back one is blinking. We got no action up here.

So let's make darn two and i know i've got the right power wire, blue white in case i do not have a good ground - let's just come here, so yeah all right, so that tells us that our short is not in the light assembly. It's not in this this section of harness from you know here to the light and the bulbs and all that stuff. So now that we know that i'm just gon na take probably off camera, because it's a pain to kind of drag the camera around and look. I'm just gon na kind of see where this harness goes that feeds this headlight looks like it goes down.

Uh looks like it's pinched pretty hard under the washer jug. I think this truck might have some kind of lift. I don't know if it's got a body. Lift in it, it doesn't look right to me.

It sits kind of funny, it's strut, spacers or something so maybe some wires are pulled tight and rubbed. I'm just going to kind of try to follow this visually without messing with a whole lot and see. If i see anything, if not, then we're going to come up with another plan, so i followed that harness down and around and despite looking like, it's pinched real hard under the washer jug against the metal kind of tweaked. It back didn't see anything i followed up to this connector under the uh fuse box here, so i just you know, lifted the fuse box up it.

Obviously somebody has been here. It's pretty pretty rough, a lot of corrosion and garbage here uh. This connector is the only one that actually popped off. Typically, these sit down in the tray and then you put the fuse box on, but we're just we're happy.

This one came off um. I got the power probe out and we can see this wire blue with the white stripe. This goes up to the front light. We should have i plugged that connector back in so we should have a direct path to ground through the bulb which we do turn this off, and if we apply power to this, that left light lights up it lights up, nice and bright, you can't see it, But, however, if it was shorted, it would blow the circuit breaker in in this, like we short this to ground, you know it blows the circuit, breaker, uh and then that'll reset here in a moment, so that reset so we don't have a direct short to ground Because we've got a nice bright light, so what i want to know now is if we reset this circuit breaker i've got plugged inside the car.

It's blown right now, i'm gon na reset that i'm gon na tick. The turning signals back on click turn signals back on and if obviously, we still have a short it's from here to the body module. So let's kick them back on okay. We can't because obviously there's some kind of power supply that comes through this connector also uh.

So i guess there's more than one way to skin a cat. We know that the short is not from here to the light. So that's good we've eliminated that it's from the body module to the box or in the box out of the box. So what we need to do is we need to find the other half of this light blue with white wire and i'm gon na see.

If i can do that without disturbing a ton here, she's pretty rough lots and lots of green just typical uh new york, stuff um, maybe because we're missing our big main power. Let's um, i see lots lots of blues and whites, i'm just gon na take and set this box back in, and you know what i guess it doesn't matter. We know we still have our short because we because we have to have because it's not in this front half so instead of trying to get power back to our box. Here, let's forget about that um.

I might have to take this out of the way here. We need to kind of turn this up and see if we can find the input where it comes into this box. I don't know why they use the box as a jumper must be for some other uh. Some other sub models that utilize a function inside the fuse box, maybe for uh.

You know once with the turn signals in the mirrors stuff, like that - i'm not 100 sure, but i do know it goes in and comes out and i believe it was on two different connectors. So i got all the connectors pulled off here um. I believe these are our two harnesses, so we've already proved that this one is the one that goes to the front of the truck see here. Yep, that is our front light output, and i believe this is connector x4, and this is our input in what are they considered? Eight yeah pin a1, so it's this pin here is where our input comes in from the body control module um.

So that is where our pin comes in from the body control module and then out to that front light. I think what we could do if we wanted to. We need to either prove or disprove the problems in the box, or the problem is in the harness leading up to the box. One way we can do that is we can actually just we know this side is good.

Going out is good. We could just d pin uh this pin coming, in which i think we could easily enough do eliminate the fuse box out of this out of the source. It is just being used as a jumper. Let me grab a little pick here.

I think we can pop that pin out. We can then plug our fuse box back in and if the problem is still there, then we just plug this wire back in and we go from this section of wire to wherever it goes inside in the body module, which i think i have to get. My readers on as all the old guys say, need my readers there. So we've got that depend and that should be the input from the body module.

Now what we can do is we will vary gingerly because we don't want this to short and yeah. Give us a false reading here, i'm just going to peel that back. I'm just going to stick it in in the harness right now. Just so it doesn't touch anything metal and then possibly so we can get to it.

I'm going to stick these connectors down in the case here, how they're supposed to be, and then flip this around when these systems are new and untouched, they work okay, but when your truck's been around the block a time or two and everything everything's kind of busted Up um makes it a little more difficult, so anyways we'll do the best we can try to get it lined up here. Just like so our circuit breaker is reset. Let's go kick on the four ways. Four ways are on and it still blew the circuit breaker.

So i guess what do i guess? I guess we didn't find the problem. Lady. I was hoping it was going to be in the box and that should be the input i don't know. If we can, we can verify that make darn 2 and i'm not screwed up on my diagram.

Let's stick this on here: let's reset the circuit breaker yep, okay, so we do have the right input. So that's that's a good thing. Folks, let's shut the circuit frame. This back off, so we know, or we should know, i guess what we could do, let's pop this back out, because we now know that that wire - i don't know if you can see it on the power probe or not, but it was flickering it uh when The circuit breaker was reset until the circuit breaker blew, so that gives me a pretty good indication that we're on the right track wire wise, i'm curious.

Then this is where it's kind of a pain in the neck. We can get these to unhook because we know we need to put that wire back where we found it put the lock back in it and technically we can double prove that the short is not in here, because we're going to stick this back in the pin That it was in i'll do that and then i'm thinking we can hook up just this one connector feed power into where this one goes into the box and it should light up the light out there uh technically. So let's just stick that right on here. They don't click in so they just set in there and then i'm gon na find, pin number two or i'm sorry, pin number one which is right here.

This should light up the light, and it does so that lights up the front light on the car, so that tells us a hundred percent. You know which we've already proved, that the fuse box is not at fault. We need to stick this back. Pin number one put the lock back in it and carry on with our diag.

Our problem is in this harness back into the vehicle. There's a lot of chicken scratch under the dash uh there's some aftermarket gizmos. In there i've been trying to kind of avoid going in there. I did give it a little.

Visual inspection didn't see any rubbage on any wires. So we've got that back in there, where we belonged right, yeah we're back on, pin one i'm going to leave this portion of it open um. I see somebody has been in here. I see there is tape, that's peeled off, so, let's just i mean it would have to be whatever we're looking for is shorted too short of the ground uh.

Our next step, i guess, is going to be unplug the body control module. I suppose we could have a dead short in the bcm. I wouldn't think so, but i, i suppose, that's possible. That's probably the next best thing to do the next easiest thing to do without opening up a bunch of harnesses and starting to look we'll go into dash visual inspection, we'll find the connector from the body control module that feeds this circuit out.

Here can say you can tell somebody's been all over this baby. I don't see any chaffage down here when i was looking and if there is most everything it's plastic so i'll give this another little look right here, but it should go straight into the vehicle and um we'll go in there. Unplug the body module leave this unplugged. We can use our power probe at that point at that point.

The circuit should be completely open and there should be no short on it. So, let's uh see if we can't figure that out so just so we're all following along uh perk lamp signal lower left upper left. We know that this wire is good. We've unplugged it at this connector.

We can, you know, supply it powered don't blow the fuse. We've gone to connector x1 pin a2 we've provided it power, it lights the light and then we've gone and passed power all the way. Through the fuse box at x4, connector number pin number one and it lights the light. However, taking um, i don't have a different apparatus here, but taking this wire right here, this is the wire that we completely disconnected from the fuse box right here at this connector we unplugged it and it still blew the fuse.

So technically, there should be nothing. These other circuits are for the ones with uh. The outside mirror turn signals which this vehicle doesn't have we're not going to discount the fact that you know there may be some monkey business under there, but i say we got to go to connector x5 pin number four on the body: control module, disconnect it and See if there is still a short to ground, if there is then well we get. We have to find it at that point.

If there's not, then the problem has to be in the body. Control module here is connector x5. So this is the connector we're looking for on the body module and uh pin number four. So it's going to be right next, to pin number three right before pin number five uh 25 pin.

I don't know what color it is right offhand, but just to verify. Pin four light blue white left front turn signal lamp supply voltage, so definitely the right one. According to the diagram uh, i just like to look see what colors are next to it, so to be next to well. Pin four is gon na, be right in the corner: light blue white: let's go find it i'll, get you guys where you can see.

So i found the connector, of course, like i say it: ain't it ain't pretty under the stash there's a lot of hack and whack and chop and cut and splice and dyson, even the body module itself is just floating around here in outer space. I believe this is the right connector. We have one two three four number three is empty. Number four has a light blue with white, i'm just gon na verify that pin one is supposed to be yellow and pin.

Two is green. I just wan na make darn sure we're in the right connector before we go nuking, something so yellow green and one i'll be right back folks, you stand by yep, one is yellow. Two is dark. Green three is blank and then number four, which is this one, which we have unplugged under the hood.

So this should not be there shouldn't be any connection here if we probe this little guy and we have a direct short straight to ground. So this goes directly to ground and it blows our circuit breaker instantly. Let this reset here, it's kind of loud and annoying you're loud and annoying power probe we get it there. We go she's reset.

So that's interesting, um, very interesting because, according to wire diagram, that just goes straight out, so we shouldn't be well. I guess we got to kind of take that with a grain of salt, we've got some blue and white. Here man, people have been god. I hate people did i just say that out loud on youtube, you know, there's a freaking bunch of hackery.

Well, i think what i need to do is i need to explore the possibilities that the diagram is wrong and see, where else, potentially, that this wire could go according to our diagram, because we don't have the turning signal mirrors. However, this truck has aftermarket mirrors on it. According to the switch, i don't think it should have park center, but you never know people change doors and panels and parts and pieces i'm going to explore the idea that this potentially could go somewhere else check. Some other connectors to make sure that it doesn't.

I hate to chase this to find out it's. You know something shorted in the driver's side door. Harness here, that sure would be a shame, looks like we've got a rogue wire there's several rogue wires, just kind of peeling around every which way i'm gon na do a little hokey pokey under here see. If we can see anything, we've got a light.

Blue with white here, what in the thunder's that go to blue with white that goes to his trailer brake controller? Right, that's interesting, and that goes to this. I must be the brake switch input. Okay, just out of curiosity, i know it shouldn't even be related whatsoever. Technically, where is it this one oops? Where are you? Okay, didn't change anything? I just wanted to be sure.

I'm gon na do some luck in here. Folks, we got ta see if we can find it. So here's something pretty bizarre folks uh. So i'm looking under the dash and, like i said i double checked per vin to see what rpo codes this truck has, and it's got, i think dl6.

So just whatever that stood for it, power heated outside mirrors, no turn signals didn't have the option that was on the wiring diagram. So i was like man. This is bizarre but, like i said, i wanted to kind of verify, because you know kind of take with a grain of salt with the factory wiring diagram say: never trust the wiring diagram. So i just simply this wire down here, our blue with white.

I just started kind of tugging on it following the wire up through and technically it should go from here to out through the firewall, but indeed i started kind of pulling on it and i could stuff my head up under there and i see the harness split And come back towards this outside fuse box and sure that wire comes up through here into the back of this fuse box, which it's not supposed to unless it had the turn and signal mirror option according to the factory diagram, so that blue and white wire comes Here and then we got to go, look at a diagram now and see. I think it comes out on one of these connectors and i'm just curious. If there's a blue and white, i don't see a blue and white coming out yeah right here. Here's a blue and white coming out.

I'm curious, i'm just going to unplug. I don't know what this connector goes to, because it has nothing to do with the fuse here. I'm just curious. Now: let's take our power probe.

I know you guys aren't optimal viewing range, but does that get rid of our short just out of curiosity, you bet you're baking, it does so that gets rid of my short. If i plug this back in does our short come back. It probably does, and i'm just curious if i cut the damn wire so that's put back in and we got a dead short back. Does this stupid? Is this stupid thing wired for turn, signal mirrors and somebody's been in the door and the wire's shorted or something in the door? Because that's the only thing i could figure.

Let's uh, i got this connector kind of freaked up over here. Let's go get a diagram and have a look just to see if this is plausible that this is like it is because it comes out in this connector. Let's just see if this blue with white is dead. Shorted on this one, also, let's see yeah.

So this blue with white is complete short of the ground and i'm curious. Let me just see what pin it is. So we can look at our diagram um. It is the b row b.

I think it's a b2, probably yeah, because that goes down to b7. So i think it's this wire rate there b2, let's go see if that matches our diagram. I'll tell you some days, cars just piss me off yep. Look at that b2 son of a husky, because so this is for when the wire comes out of the body module and it goes down here and it splits.

This is for cars with option code, dl3 so delta, lima, 3 and delta pop in november. So dpn dl3 and then it goes this way, and this one, as you can see by the minus sign, is for this. Wiring harness is for cars without that. Well, ours has option code.

Dl8 17 inch mirror outside left right, wide load, heated two panel, blah blah blah. We do not have dl3 or dpn according this vin. These are the only d codes that we have according to the vin, and particularly this one here for the mirror. So technically we shouldn't even have this, but obviously we do and it goes to the door, lock switch driver side and we got ta assume that all these wires are here now comes down.

I'm going to tell you what none of this matters, because this does not even have an led on the outside of the mirror, which is indicated right here that it that could have i'm not going to tear the whole door apart. But i'm going to show you what we're going to do stupid car straight one. Do i got a straight one there we go we're going to see if we can't just go full captain caveman on this thing. Now we've got a red latch in there.

Let's see if we can't get the latch unhooked, okay, get the red latch out. Let's just see if we can't take this wire out plug the rest of this crap in so there there's that wire. So there's our blue and white wire we're going to take that right out we're going to leave that out which way did this go? I forgot this way, yeah sure, let's plug this back in oops properly, if we can get it. This is probably the rest of the door accessories, so we're gon na take and leave this wire pigtailed out um.

Now technically, we should not have a short here which we don't so i'm plugged in under the box, no short there. So now we should be able to plug the body module in in the fuse box and i'm betting. We got turn signals fuse boxes in breakers. I didn't put the light back in it's still sitting there breakers reset and then just to review, because i had some company stuff in here for a minute.

This is this is uh our circuit breaker, where it hooks in there uh, just in case you're wondering what this is. This is mine. That's where the circuit breaker hooks in in place of the fuse. This, let me set this light down, give everybody vertigo.

This is the single wire. We depend that clearly goes. You know into this door that technically shouldn't um and then i plugged the body module back in and of course, like you know, he's got all the extra wiring hanging down just like that fella logical deduction. We now got our blinker and we got our blinker.

That's it folks show's over easy peasy. Well, that's the hard part, i suppose now the easy part putting things back together. The nice thing was: is that somebody's already come through and broke everything busted connectors cut wires. Sometimes that stuff frustrates me, but then sometimes it makes me happy because it makes things easier to get to and then you can be kind of a slob just putting stuff back together because well i try not to try to make it a little better and i Found it, but you know what i mean uh, i don't know what else to say.

We just used some logic and some thinking and a little past experience of getting your ass kicked a time or two on a car. Assuming the factory diagrams are correct and assuming the rpo options are correct and assuming that the wire can't go there because the diagram says it doesn't, that is the valuable information i don't try to memorize it or understand it. Why manufacturers do what they do. In my opinion, this is strictly my opinion.

I would assume that all of the chevrolet trucks and gmc trucks would have that harness regardless if they had the mirror option, simply because from a manufacturing standpoint i would assume that would be easier to do than to make multiple different harnesses for multiple different rpo codes. I would think that they could manufacture the harness to fit all rpo codes, every single option and then just have it there with you know blank ends like well. It's there. This harness has 12 wires in it.

On this end of it we're only going to use four of them, so i would just think that would be easy and less confusing. But and maybe that's the way, it is, and maybe that's why we're having the problem that we're having and that's my misinterpretation of wire diagrams, but anyhow, neither here nor there all that's left to do is put a little jiggly bits together here folks and then go Upstairs and get us a 15 amp fuse, stick it in the hole, call it a day, then we'll call this fella tomorrow. Let him know that his truck is fixed and then he didn't need a fuse box or any of the other crap they put in it. Where is the wire shorted? That's a great question.

Uh somewhere is between there and in the driver's door to me at this point it doesn't matter because it's an option that runs through that door. That's not used, it's uh like say, somebody's been in this door in order to put the aftermarket mirrors on it, so i'm willing to bet if we took the time to take the door panel and stuff off, we would find where it's short, where there's a screw Rubbed through it, where the wires were removed and they're pinched in the door perhaps someday at a later date, the other wires that are with it that are probably pinched to or screwed up will will show up. But who knows i'll see what the guy wants me to do and i'll tell them what we did and what we found and i'm just going to take and tape that harness tape that wire on the harness in case at a further date. Somebody wants to add the mirrors with the turn signal options i don't know, but what i want you to do, while i'm waiting for that date to come, is to head on down to that comment.

Section leave your questions, your comments, your concerns, wait on your subscribe ring the bell to insty the facebook, and you know what to do folks. Just for my reviews, if i can do it, you can do it thanks for watching hey.