How to test an Alternator (not charging from a blown fuse) - Mazda

How to test an Alternator (not charging from a blown fuse) - Mazda

SUBTITLE'S INFO:

Language: English

Type: Robot

Number of phrases: 650

Number of words: 4829

Number of symbols: 20468

DOWNLOAD SUBTITLES:

DOWNLOAD AUDIO AND VIDEO:

SUBTITLES:

Subtitles generated by robot
00:08
1997 Mazda Miata with a 1.6 liter engine and what we're going to be doing today guys is a charging system test this vehicle was brought in with a dead battery customer what complaint was he was driving in to work and some of the interior components stopped working the radio shut off and I believe he said his dash lights quit working as well and then the car died and would not restart another symptom he had mentioned to me was a few days ago his tachometer quit
00:42
working not sure if that's related or not yet so what I want to walk you guys through is some charging system tests so what I like to do before attacking a charging system is I like to look at a wiring diagram there's just so many different designs out there and I need to know what I'm dealing with I need to know if it's computer controlled or not and so I pulled up the diagram for you guys and what we're looking at here's your alternator right here you see it's grounded on the housing we have a solid
01:14
white wire that's going to a main fuse and then that's coming directly to the battery so that's going to be your heavy cable going to the starter that's hot all the time and then we have another wire it's white with a green that's coming from the main relay that one's going to be hot and run if it's from the main relay and then we have another one that's the bulb circuit for this alternator so when we do our text we're going to start with the heavy gauge white wire with the car running and then we'll move down the line and then we'll
01:46
talk about the results of each one all right here's a shot of our alternator sitting in this location down here and what we can see in the camera right here this is our B 80 post that's the heavy cable that comes to the alternator and behind this hose there's a two pin connector down here hopefully this will show up it's right below B it's right in this area here and I'll get you another shot on that when I'm doing testing on
02:18
that but for now we're going to look at the voltage level on the B 80 post of the alternator my hookups yellow lead is going to the B 80 post that B my voltmeter positive lead my negative lead for this I am going to the valve cover the battery is in the trunk on this car ideally I'd want to go to battery negative but I can't for this test at least not easily and we're looking at a voltage reading right now
02:50
of twelve point five eight and I've had this battery charger on here for a while so this battery should be at least halfway decently charged I don't like this test this isn't good enough I want to start this car and see what kind of voltage we have on this post so I'm gonna go ahead and do that you guys can watch the bulb ear okay what we normally do is is we check this at the battery first and I skipped that part batteries in the trunk I'll take you back there next you see we have twelve point one to twelve point one one volts on this system right at the BAC
03:38
post what that means to me is this thing's not charging and what we want to do first is make sure we don't have a voltage drop between the battery and here you know really it's not necessary when you have that kind of voltage that's pretty good but let's check it anyway it's procedures that are important here so to know what my voltage drop is I have to take another measurement at least that's one way to do it and subtract the two and then I'll show you the actual power to power voltage drop test so remember that it's number 12.1 one up here let's go back to
04:09
the battery okay for my lead connections back here at the battery I have my black where you going to battery negative and my yellow lead scope positive going to battery positive you see at the battery we have 12.1 6 volts so that means we have a point zero five 50 millivolt drop on this circuit roughly between the battery and the v80 post what that tells us is this positive cable going to the alternator is fine now there's another
04:41
way to do this and it would be important to know how to do this when you have changing voltages on the system especially in light of a weak battery if this voltage was dropping rapidly while you were doing your tests then it's kind of hard to calculate that voltage drop unless you're monitoring the circuit directly so to do a proper voltage drop test what we're going to do is we're going to leave one lead on battery positive and then we're going to compare our voltage to the B 80 t-post of the
05:11
alternator and I'll get you a shot up front of that just know that I'm going to leave one lead on battery positive back here for this next test and I'm going to have to use a jumper wire to do it because of the length we have here between the two so I'm using a jumper wire for this because my leaves aren't long enough and I'm going to compare this side battery positive to the B 80 post of the alternator see my jumper wire connected here let's go up front here's the other end of my jumper wire
05:42
being very careful this doesn't touch anything metal this is plastics that this is sitting over top of so we're fine here my yellow leaves connected to this polarity doesn't really matter here guys you can put your black lead here in your yellow lead on the dat post of the alternator or to say that differently you can use your volt meter positive or negative here positive or negative up at the v80 post it does not matter it's kind of tough to see to see my black lead is down there on that v80 post and then you
06:13
guys probably saw the voltmeter already we have a point oh six of a volt drop on this circuit and so again I wish I would have shown this when the battery was weak before when we initially tested the alternator the system voltage was dropping rapidly while we were doing our test because the battery didn't have a good charge and the runtime involved with causing voltage drops and so when you do your measurement in the back and you measure it upfront and you subtract
06:48
the tube for your drop you really weren't getting a true drop reading we were getting maybe one to two volt difference saying we had a two volt drop in the circuit but system voltage was dropping and so this test was needed in that scenario so you know what the proper voltage drop is on that circuit this is a power to power voltage drop test and I know it's kind of strange for some of you but what you need to remember is a voltmeter reads difference in potential and so the difference in
07:19
potential between my BAC post and my battery post is 0.06 for 60 millivolts nothing wrong with that at all it wouldn't matter if this read minus 0.06 that would just be with your leads reversed and as far as a number you guys probably going to want to know a number truthfully you really don't want much difference between these two especially on a heavy v 80 post maybe a maybe a few hundred millivolts at most in particular when the system is actually charging so nothing wrong with our BAC posts cable
07:51
to this alternator we need to move on to these other wires now alright kind of tough to get this shot but I'm on the 2-pin connector now on the alternator and the wire that I'm on is wait with the green wire that comes from the main relay and my scope positive or voltmeter positive going to that wire and my voltmeter negative back to my intake manifold or my valve cover and there's my voltage reading eleven
08:21
point nine six the voltage drop on that circuit again we would subtract source voltage but this thing's not charging to the source voltage has probably dropped and if you wanted to get a voltage drop measurement I still have my jumper connected here we can do that I'm on battery positive and all I'm going to do is take this lead off here and this isn't really necessary I'm just showing you procedures the drop on that circuit is 0.08 so of
08:53
course that they're just going to have a little bit more of a job because you're going from the battery into the car into the main relay from the main relay back out to here there's a lot more wire there's more components involved so eighty millivolts on that circuit not a problem to clean one less generally do these with an alternator I just want to make sure I have near battery voltage on one of those small gauge wires I think as a rule I think what I normally follow
09:22
is that I want to see a main power that heavy b8e cable that equals battery voltage and then I want to see at least one more wire go into this alternator that reads battery voltage we can call it a control circuit if you want to now we got one more circuit we need to check and that is this bulb circuit so I'm gonna move my leads now let's get to sorry here's a better shot of our to pin connecter and I'm now on the top wire which is the bulb circuit and we'll get
09:55
a voltage reading on that now by the way that wire is white with a black tracer this is the one going through the bulb circuit and the - and you see I've low voltage on this circuit point zero - and the thing about that is I'm not sure what I should have on this I know that the bulb is ground side controlled if you want to call it that by the alternator let's go back to the diagram we'll talk about all right as far as the bulb circuit this is where we're measuring this right here we're reading 0.02 of a volt and we're not sure what
10:27
this circuit should be we know that this is the ground side of the bulb circuit and at certain points in time we're going to have 12 volts here because we don't want to have this light lit and at other times the voltage is going to be low to make that light light and the thing about this that's missing really in this picture too is the voltage regulator which is all internal to this this is the entire a alternator system diagram there's no computer involved there's no field circuit control by a
10:59
computer it's all done internally and what you guys need to understand about these is sometimes the bulb circuit is needed to wake up if you want to call it that to wake up this alternator and have it start charging and so my suspicions here or that we potentially have a bulb circuit problem so what I'm going to do first is I'm going to give you a voltage measurement here with the key on and the engine off I just showed you one with it running we're at 0.02 let's get you back
11:32
to the car and check that with the engine off I would think at some point in time I should have high voltage here if this bulb circuit is functional another thing that I've had good success doing with these is substitute what the bulb would do and so if we think we have a bulb circuit if we have a cluster problem or if we have a fuse problem up here we could take a test light right here and go to back battery positive which is really
12:03
essentially what this bulbs doing we're going to positive when we touch it on there if this alternator starts to charge then we know our problem is over here on this side of the circuit so that's what we're going to do I'll give you the voltage measurement there first and then I'll show you the test light test all right there's your Keyon voltage reading on that wire you see no change here at all and I'm telling you guys from my experience from engine running to engine off you're going to see a difference on this circuit any bulb circuit that goes
12:33
to the alternator I'll start back up again let you watch it so they're going to change point oh two of a volt all right so what I'm gonna do now get you a shot down here she's going to take my test light the battery positive touch on that same circuit all right so here's my setup I have my test light going to battery positive using my jumper that was in the back now you can use the BAC post if you want it was just interfering with my camera and when I
13:15
touch ground this tesselation light as you can see in the picture okay and so I'm going to take this now I'm going to go down to my pin that is still on this bulb circuit it's got this red insulator on the end of it and what I'm going to do is I'm just going to touch this on the pin to take a listen to the system you actually be able to hear it if this thing starts to charge engine just got a little bit lower idle speed
14:02
my bulb is dim not really relevant for this take it back off definitely heard that alternator kick on I'm gonna give you a voltage reading on the system so I'll just go back now to this terminal that I'm using in the back connected to the battery positive I'll give you a voltage reading here and I'll let you guys watch while I'm redoing this test okay watch the voltmeter let's connect
14:38
this test light now to this pin and you can see we're now charging 14 volts I like that this battery is weak too so once this battery charge is up a little more that voltage will be a little higher that's why it's really bogging this engine down is it's uh in a way almost full fielding the circuit dead battery high amperage law 2 horsepower dream so as I've just shown you guys a bulb
15:17
circuit malfunction can cause an alternator to not towards I've seen vehicles come in with this problem that have had three batteries and three alternators before they finally gave up on it because they don't know how to do proper voltage measurements on an alternator I've seen this same condition on a Volkswagen we now see it on a Mazda I just helped someone on IAT n recently with this kind of situation this is the exact test I told him to do with his car he was having issues with the alternator
15:51
of course and he was concerned about the cluster and the dash and having to go in there and check in the bulb circuit and what I had told him to do is this exact test and so think about it if you do this test and that alternator starts to charge you don't need an alternator you don't have a wiring problem out here you definitely need to pull the the cluster that was his situation where we're at now we're not ready to do that let's go inside the car now and take a
16:21
look at what we're missing can't turn the key on first simple bulb tech there's nothing we have no indications on here at all he is in the on position I'll start it my gauges are not moving my tachometer is not moving I have no turn signals you know these are all things we were not aware of up front and I know some of you guys are thinking that why don't you just check
16:53
the fuses in the first place the point is this what do you do when you check the fuses they're all good you check the wiring to the alternator it looks like it's good you're not sure about the bulb circuit that's the point of knowing how to do this it isn't always as simple as checking the fuses and you guys that say that to me you really don't know what's going on of course we check the fuses of course we do those basic checks but in the real
17:26
world it doesn't always go that way and this could have been like the Volkswagen that I had done in the past where everything looked good and it looked like it needed an alternator what we focused on that bulb circuit and we had enough evidence supported by this test that we're doing with the test light doing the bypass test that said hey we have a bulb circuit for sure that's causing this issue it's time to pull the cluster and on some of these cars pulling the cluster is not an easy task
17:58
so think about that for you guys that have this mentality of oh he show to check the fuses first that isn't the point of what we're doing here you know it isn't always this easy yeah in this case the fuse was blown as you're going to see here in a second but guys again the vision here think about it everything looks good fuses are good what do you do now do you have enough evidence that's the point okay back to our diagram you see we have a meter fuse right here that we're worried about and
18:29
it's a 15 amp on a 97 10 amp on a 95 96 and that is in the fusible the fuse block which is the left kick panel area so we're going to take a look under there and see what we find before we go toward the cluster as a problem so we're worried about this in fact with all of those other things not working we're pretty sure it's that let's take a look alright this part is gonna be tough to shoot here I'm laying underneath this tiny car using a test light my favorite
19:00
tool for locating blown fuses and all we were going to do is just run down the line here look for our light to light and what we do is we just go on the backsides of both of the fuses so for some of you guys that are following me you're like I know get on with it but there's others that don't know it's that simple to check a fuse both sides should light and just going to go right to it this one right here we're lit on one side and we're not lit on the other and that's our blown fuse now if you have
19:32
any let's go down the line here if we have any that don't light on either side that's not necessarily a problem for example you could have headlight circuit that's off might be fuse protected I know honda does that and if you don't turn the headlights on of course it's not going to be powered up so we only worry about no power on both sides of a fuse whenever that's the circuit that we're worried about so in our case we're worried about the meter fuse if our meter fuse was dead on both sides then
20:05
we would be concerned but in this case we don't have any circuits like that anyway we just have this one here this is definitely a blown fuse so we're gonna pop this thing out put a new one in and see the result of that as far as our charging system and everything else all right we have the new fuse installed but turn the key on you notice we have - lights that we didn't have before and I'm gonna start the car let's watch
20:35
our TAC TAC is operating now we do have a check engine light on this vehicle - something else that will need to be looked at let's see if our turn signals work they do and let's go under the hood now and see what our charging system voltage is okay my lead connections I'm still meter positives going to my jumper wires going back to the battery and my meter negative is this black connector
21:09
right here on the valve cover you see on the reading 14 volts so that is a fix as far as the charging system goes that the reason why this thing died on him is that fuse blew now of course something caused that use to blow we're going to have to look at that - I think what I'll do is I'll make that a separate video we'll walk through the sorts of ground tests on this circuit that's if I can even find it depends how intermittent it is worst case scenario is we can't duplicate this as I send him away with
21:39
an extra fuse and come and bring it back to me if it blows again I work with the guy so I have that luxury but that's that's good 14 volts on the charging system unfortunately guys in our field there's a lot of people that would have put an alternator in this already before doing these checks you know probably put a battery in it - I get that all the time you know car comes in with a dead battery everybody wants to automatically
22:11
replace the battery well here's an analogy your kid has a power wheel and you charge it right you plug it in well when the kid when your kids Power Wheels battery is dead from driving it do you replace it every time and the no I mean sir car batteries aren't meant to be deep cycled like that but one time that battery goes dead is not going to kill it so we don't need to rush and put batteries in cars and throw parts at cars and put alternators in again ah I
22:42
know I've said this but I've seen this kind of symptom with three alternators and three batteries and just a basket case by the time that I would get it and it's got to be aware of it the bulb circuit is the turn-on for some of these alternators so while we're talking about the bulb circuit again why don't we look at it now with a good working circuit so we have a good baseline to go by and what I'll do is I'll get you back on that bulb circuit wiring we'll look at
23:13
the voltage with the kyo-ahn we'll look at the voltage with it running and I'll just keep you where you're at I think you guys be able to see that I'm gonna take my don't lead off the off of the battery and I'm going to take this down to my bulb circuit I'll leave my ground connected where it is this is my bulb wiring I'm still connected to it from before here's your bulb circuit with the engine running 13.6
23:58
13.7 and let's think about that for a second we have three wires on this alternator and I know it's grounded on the housing and you know the ground issue wasn't the case with this car something to consider though - if you have a no targe and all your voltages are corrected throw a lead on the housing of the alternator compare it to battery negative in this case we're going to want to have a jumper to go back to the battery it's in the trunk do a voltage drop test on the case we don't need to do that here think about this this car comes in be 80 posts you
24:34
have battery voltage the wire that goes to the main relay you have battery voltage and the bulb circuit you have battery voltage you're done the wiring is good check the housing for your ground and then put an alternator in it so there's your voltage level what's keeping the bulb off guys is to power fees so if you look at this diagram real quick we're powered here by this meter fuse that I just replaced on this side and then we actually have voltage on this
25:09
side of the circuit too so it's either the alternator is sending voltage or we're just not giving it a ground I don't know enough about the internals of the regulator to answer that I might be able to with some other test light tests let's take a look at it with the key on engine off and see what it looks like and remember key on engine off would be when you want your bulb check all right we want to see that light light key on engine off so I'm expecting a ground on this circuit so let's see what it looks like just going to reach in turn appeal that is key on engine off 0.72 of a volt
25:52
and my guess here remember we had point zero two on this when we started my guess here is this circuit now has a ground let's look in the dash see if this target light is on yes I do have a charge light that is on has a little picture of a battery says charge underneath it and I'm just going to leave it the way it is take my test light - battery positive still got my jumper back here from before what I
26:32
suspect is this light in the light on this alternator make sure your light works before you do testing I'm gonna go down I'm going to touch it on the same circuit that's in the shot or not and just rest it on there for a second all right I have my test light leaning on that on that pin and you see my light
27:17
is lighting so with the engine off we have a ground on that circuit okay and with the engine running there is no ground on that circuit and again I don't know the internals of this regulator that is somehow turning on this voltage regulator with that missing bulb circuit this alternator will not charge this
27:48
Mazda is not the only one that does this Volkswagen Mazda I think I've seen it on GM I think I've seen it on Ford so be aware of it I think it's a real good one real good lesson little voltage drop measurements in there some alternator basics pay attention to what you're doing don't be a parts changer now what we'll try to do for part two is we'll do a short to ground test on this meter fuse and hopefully we can duplicate it
28:20
we'll walk through all the procedures of how to know what's all on that circuit what caused it to blow and hopefully we can duplicate that so for this one though I'll stop it there blown fuse again not the final fix we need to find out what caused that fuse to blow but the fact is this car did not need a battery this car did not need an alternator almost forgot I get these questions from you guys a lot and I think it's important to cover it on this one what kind of test light am i using
28:51
for this using a regular incandescent bulb type test light I'm not using an LED test light for this I don't think an LED test light would work for the bypass test I showed you I don't think it would carry enough current to wake up that voltage regulator so regular incandescent test light I mean you can get these at Sears for like 20 bucks so so hopefully that answers that question from you guys because I know I get that a lot so thank you very much hope you
29:25
guys like that you

DOWNLOAD SUBTITLES: