You should have done your measurements with the connector disconnected, than you would have seen your Voltage! Great work! Nice to see you work on European Cars!😎👌
@EverythingNausome6 жыл бұрын
Agreed.
@aymenbouzouita89565 жыл бұрын
We want an educational vidéo of charging system Dan ! And thank you
@5Dale656 жыл бұрын
Same symptoms you'd get if your battery light bulb is burned out, or if the brushes inside the alternator are almost ready to go. One more thing. Your charging bulb is in parallel with a small resistor in most cars (located in the cluster), so in case it burns out, the alternator will still charge right from the get go. Here you had a broken wire, so the alternator was totally separated from the cluster (from the bulb and the resistor as well), hence no charging at all at idle.
@baxrok2.6 жыл бұрын
Nice diagnosis. I'm still trying to work out that light circuit function but do appreciate you taking the time to explain it. The comments are very helpful as well, so it's a good discussion. Thanks!
@EXOVCDS6 жыл бұрын
good catch... basic stuff that the first guy (alternator installer) should have found.
@Mad4Tracks6 жыл бұрын
Wow, I have seen this charge issue on a 1.2 TDI Polo once, would not begin charging after raising the rpm above 1500 one time. after that it would charge fine. Customer didn't see a problem in it as he drove like that for months already. Can't tell if the battery light didn't work though. Nice diagnosis! Will keep that connector in mind.
@hardya056 жыл бұрын
Great video, just spent an hour thinking about the exact same symptoms on my wife’s car, no charge of battery on initial start up, Rev the engine and all fine, not a problem when you know this happens but couldn’t think why it’s happened in the first place, thanks for the vid saved us a lot of time.
@codywichman2136 жыл бұрын
I've personally seen on a few imports, the alternator default strategy is to charge once it hits 2000+ rpm. Even if there is no field control or no wake up signal present. If an alternator will charge off idle ok and continue charging until the key is cycled its a red flag for no control/ excitement. Usually wiring related. But I have seen bad voltage regs too
@josephwash1096 жыл бұрын
Interesting. As other viewers mentioned, a lot of manufacturers started adding a resistor in parallel with the instrument cluster warning bulb. The idea was that the bulb and resistor in a parallel circuit have a lower resistance, so excitation current is greater to set up the field in the alternator. If the bulb burned out, since they were incandescent bulbs, the resistor would still pass current to allow the alternator to continue charging. I suppose, since newer vehicles use LEDs for instrument cluster warning lights, which, in theory, should never "burn out", the resistor is no longer used as a fail-safe in a parallel circuit. The old General Motors 10SI alternator, for example, has the parallel resistor internal inside the alternator case, so even an external bulb circuit problem wouldn't affect alternator output.
@prmayner6 жыл бұрын
I had to laugh when you showed the Pico and said CHECK IT OUT, SWEEEET. Awesome glad to see you got yourself a Pico, Love the vids, Thanks for uploading.
@orville585 жыл бұрын
By far one of my favorite videos on alt. Diagnosis congrats on the pico it is sweeet
@guayaco-dm3vu6 жыл бұрын
Somebody got an early christmas gift... Great video lime always Tom
@Jpilgrim306 жыл бұрын
Pico 4425 is definitely SWEET. I love that thing. The only thing that they could make better is if the next automotive version has 500 volt inputs so no need for attenuators at all.
@johngonzales46316 жыл бұрын
The current from the globe flows through the rotor and back to ground through the regulator. This small rotor current flow is enough to generate a magnetic field. As the alternator increases in speed the D+ diodes provides power to the rotor and 12v. on the D+ circuit. When there is no initial current flow on the rotor from the globe, there is no initial magnetic field on the rotor and it is necessary a lot more alternator rpm before some voltage is generated in the D+ diodes
@billyr98406 жыл бұрын
Pico, NICE !!!!!!!! Good call and glad you went back to figure out how the system worked !
@MrBorntoroll6 жыл бұрын
Hey Tom, thanks for sharing. Good explanation of charging system. Lamp circuit current in fact travels through field coil to the ground which can be disconnected by a voltage regulator (it's job in fact) by means of a transistor. We can check for 12 volts unplugging the connector at the alternator. Also check the bulb circuit by grounding L circuit at the connector to the alternator. Also check alternator by providing through a testlight current to the L terminal of the alternator itself ;) The question: Why it begins to charge at higher RPM? )))
@phoenixautodiagnostics42096 жыл бұрын
Got me thinking too.
@MrBorntoroll6 жыл бұрын
I don't know for sure but based on a very good video kzfaq.info/get/bejne/edqln7Wi39TGqn0.html my thought is that the core of the field coil is a bit magnetised as a result of previous field coil operation. But it is very weak magnetic field so you need high RPM to get any juice from it. Seems legit from my point of view. Opinions? )))
@robertwhitworth73465 жыл бұрын
This issue coupled with a poor battery creates HAVOC! Start car let idle, any heavy load device won't work (rear defrost, slow windows harsh trans shifts, heavy power steering the list is long). The fun part is they are all intermittent as soon as the regulator is manually (default) energized all the problems go away. I found it by plugging a cigarette lighter digital volt meter in and noticed 10.8V at idle with a host of issues (intermittent) raise RPM and they all go away. Great find and interesting to see how the grounding of the battery bulb through alternator at rest works.
@transam86074 жыл бұрын
You just opened my mind up on something I would of never figured out I'm going to check step by step what you showed and hopefully I finally fix my issue on my 08 2.5 jetta thank's a million.
@raphaelfrancisco89 Жыл бұрын
Did you ever figure out what was wrong?
@haywardsautomotive61566 жыл бұрын
You're going to love the Pico Tom...good investment and the detail is great. Great video, diagnosis & repair Tom!!
@exmotorsports6 жыл бұрын
Great Catch on that harness Tom.. Looks like someone used a yard dart to back probe those wires some time before and got the green crusty disease..Dang! And Thanks to 5Dale65..saved me a bunch of typing. I was about to say the same thing about the resistor and the burnt bulb too. Good call.! Typically a 510 ohm resistor. At least Ford does anyways. Cheers (:
@for2utube6 жыл бұрын
In the old days (when cars had only an ammeter on the dash) the ammeter was not sensitive enough. You could drive a battery flat and not really notice (driving only in daytime and no accessories). Car makers wanted a idiot-proof light that would tell the operator when there was no charge. The ammeters disappeared from the dash; the light remains, and you might have a voltmeter but the light is in every car/motorcycle/lawnmower/tractor. And, the light came after customer issues using the ammeters, so is designed to be more idiot-proof than the ammeter.
@rcpilot822 жыл бұрын
Thank you so much. You just helped me resolve this exact issue on my wifes 2010 beetle. Ironically that same connector have me issues a few years ago with the AC compressor not kicking on. I am south east of Pittsburgh, small world.
@mraccord926 жыл бұрын
haha as soon as you said battery light doesn't come + charging system will kick on after revving over 2500RPM I knew it was that dash light wire. Had a 92 VW Jetta with that very same issue. swapped alternators thinking it was a faulty unit and it still didn't work. Someone on a forum mentioned if the dash light didn't come on to put a meter on the system and rev it to 3k and if it started charging then it was this single pin wire coming out the alternator that goes through a diode to the light on the dash. Sure enough found a corroded wire around the battery. Nice fix dude!
@markferraro52506 жыл бұрын
excellent video Tom great news on the Pico love your videos one thing brought to mind was using an led or low amp test light hooked to bat pos and the other end at alt term from cluster that was broken and see if light comes on KOEO and goes out KOER and always charges 14 volts scannerdanner had a mazda miata with cluster fuse blown that caused similar thing thanks again
@HeyBirt6 жыл бұрын
Old VW's ands some old Chevy's used this same system with the added fun that if the bulb burned out your alternator would not start to charge. One some cars they finally got smart and put a small resistor in parallel with the bulb so the alternator always got the excitation current. If you had never worked on one of the old VW's this would have been hard to find. Good job.
@markmcgoveran6811 Жыл бұрын
You miss one thing. The alternator was excited from the residual magnetism. I've been wanting to listen to this speech for sometime today I have a Volkswagen beetle 2001 diesel died last night and I'm jump starting it today and I'm hoping that I can stick to magnets on the outside of the alternator and tickle the charge up a lot earlier than it did before and if the lightbulb goes out the lightbulb goes out it's just going to be a lot quicker to jump up and charged
@joeserrano92666 жыл бұрын
If you want to see voltage on the bulb wire with just the key on you have to disconnect the alternator cause the alternator in grounding your voltage
@garyfischer53355 жыл бұрын
Thanx for the video..........Saved me a ton of work swapping out a good alternator for a new $200.00 one and would have still had broken wires and no charging .....Soldered additional wire pieces in and Bam 13.9 @ idle ......... Thanx Again
@n124lp5 жыл бұрын
Interesting case. Thanks for sharing.
@zvonimirbobicex-49626 жыл бұрын
also, you should write corrections on the screen(mr. scandan does that)..like, when u say: "..there should be 12V that comes from the cluster.."..written: "no, i m wrong, there should be 0V key on, but the bulb should be lit. i will explain later in the video"..man it s your reputation..after all you are mr. scandan for the euros..the world is watchin! :)
@zvonimirbobicex-49626 жыл бұрын
always check voltage/gnd on each side of a broken wire! ;)..bcus, wires are mostly insulated, not exposed..so, when opportunity presents itself, why not? :)
@shaunsautorepairs54106 жыл бұрын
Good video...paul danner would be proud..lol Initialy i would have suspected a blown bulb in the dash..
@train49052 жыл бұрын
Exellent find tom,well done.. Ste fro uk
@bellaboo6098Ай бұрын
Very good vid. Great job! More 😊please😊
@throttlebottle59066 жыл бұрын
"control module", so it probably senses rpm or gets signal from pcm saying engine is running, then excites the wire to start charging. many cars wont excite it for so many seconds after engine start. it would be interesting to watch that wire on a scope from initial key turn to running :)
@nemanjadzombic61015 жыл бұрын
Greaat and clear explanation on how the system works. excelent video!
@nicknicu17876 жыл бұрын
Good job Tom! Thanks for the video! 👍
@johnshere49226 жыл бұрын
Hi . Good diagnostics All Bosch alternator got a fail-safe build in to charge when rotor speed reaches 5000 rpm. First charge fault check is the charging charge lamp. no lamp open circuit, a normal fault is worn brushes. Charge circuit turn a transistor on and residual power from B+ to D+ on reg to Positive brush, rotor, neg brush to earth
@ws26646 жыл бұрын
no tom that's not it, when you turn the key on engine not running the voltage regulator sends a ground to turn on the bulb when the engine starts the voltage regulator takes the ground away and the bulb goes out your only going to have 12 volts there when the engine is running, if the voltage regulator quits while the engine is running that ground will be applied and turn the bulb on, you way over complicated that.
@gptechtronics8526 жыл бұрын
I thing you are wrong. Check again from 6:10 ...
@Playboifresh2515 жыл бұрын
I got a 2012 vw jetta Se charging problem. Battery is dead every morning I have to jump it off. Bart. Good alternator good. I'm confused don't know what's wrong with it.
@Playboifresh2515 жыл бұрын
I only had it 6mo.
@d.d41845 жыл бұрын
That's exactly what he said.
@carey101015 жыл бұрын
From my knowledge the battery light only turns on after the voltage drops to around 5 or 6 volts. And reving it up to 2500rpm ussually means that u have a intermitten alternator
@dailyobedience52646 жыл бұрын
Sweet pico bro. A game changer for sure. Good video. We need more euro stuff. Keep it coming.
@carstengotfredsen1606 жыл бұрын
GREAT VIDEO 💪 💪 💪
@billyyoder81716 жыл бұрын
Hi Tommy. If you ever get a chance to diagnose a charging system on a newer VW with two wire connector, one wire from ECM and other wire from Vehicle Electrical System Control Module, would greatly appreciate it. Can't find any diagnostic info on what should be expected on the ECM wire nor VESCM wire. Would like to know who supplies what and type of voltage to expect on these wires when unplugged KOEO. Also if the voltage regulator terminals should have a voltage on them when the connector is unplugged. Also what the signal should be when plugged in and charging. Thank you Tommy. I appreciate your videos.
@mathiasjohani21306 жыл бұрын
Wouldnt you see 12 v unplugged?
@saintsfan72683 жыл бұрын
Where is the fuse for alternator? What is the number for fuse ?
@throttlebottle59066 жыл бұрын
that's why I like volt meters in the dash :)
@eastpantherbenz6 жыл бұрын
Attack of the green crusties!
@rrmech116 жыл бұрын
Nice job
@Automotive_Solutions6 жыл бұрын
Nice. How many people would have put an alternator on this first?
@Diagnosedan6 жыл бұрын
Automotive Solutions i think 9 out of 10!
@tcifusion44976 жыл бұрын
NOT ME MY FRIEND....ALWAYS CHECK UR LIGHTS FIRST.....THOSE CARS CAN BE TRICKY TO DIAGNOSE ALMOST 8 OUT OF 10........19 YEARS WORKING ON THEM THEY STILL AMAZE ME............THEY WONT TRIP ME THOUGH.......ALWAYS DOUBLE CHECK...THAT IS THE BEST WAY TO DIAGNOSE THEM.....GOODNIGHT FROM GREECE MY FRIEND....
@anilec3335 жыл бұрын
All the garage shop in Macau, they will put new alternator first and charge the people 💰
@phoenixautodiagnostics42096 жыл бұрын
Another nice video
@billrimmer55966 жыл бұрын
Nice diag!!
@dudleyflodeen64286 жыл бұрын
what if you have a flashing battery light
@bobzak95082 жыл бұрын
Was that connector at the alternator or where? I have an 06 that the battery doesn't charge either, ever...
@PositiveLeadDiagnostics2 жыл бұрын
The 4 pin connector is near the starter
@1984juant6 жыл бұрын
Nice video
@MrBugsier56 жыл бұрын
burned out light bulb on alternator,or bad wire. ., (no start voltage to regulator.) after hitting the gas the remanent magnetism kickes in and overide the light. after that the alternator kicks in. , so loose wire or burned out light.
@mw3designs2 жыл бұрын
Where is the location of that 4 pin connector? Did you access it from under the vehicle?
@PositiveLeadDiagnostics2 жыл бұрын
It’s easier to access from underneath. It’s near the starter
@billyyoder81716 жыл бұрын
Tommy, concerning the W terminal, does the ECM supply the voltage to the regulator and the regulator creates the pulse to ground for the feedback monitor signal?
@PositiveLeadDiagnostics6 жыл бұрын
I believe so. I know it’s not computer controlled but it is a monitor
@semifredigmailcom3 жыл бұрын
what is this howling sound from the engine? I have exactly the same, I just can't find the reason, howls loudly, especially when the engine warms up
@ahmedhammoodiMD3 жыл бұрын
It’s a 5 cylinder, sounds usual.
@dudleyflodeen64286 жыл бұрын
what kind of voltage should you have coming to the alternator from the each of the 2 wires and which goes to ecm and which one goes to the instrument cluster
@PositiveLeadDiagnostics6 жыл бұрын
The wire going to the ecm should be a square wave and is just a monitor there is no control from the ecm. The other should be 12v from the cluster for the exciter circuit in the alternator.
@JamesLee-oe7mt6 жыл бұрын
Guess it is self exciting if you get enough rpm
@anilec3335 жыл бұрын
My friend bttele battery keep drain. He changes almost 10 batteries within 3 years.
@pskauto67986 жыл бұрын
Nice diagram
@MrAndresinibus6 жыл бұрын
I have a somewhat weird issue I replaced the voltage regulator and car still won't charge if I apply direct battery power to the wire coming from the computer bypassing the computer it will charge goes up to 15 volts but as soon as I put a load like the ac or lights and the power at the battery drops it goes back to 12. Some volts if I kill the loads it jumps right back to 15 v could this be a bad regulator? Thanks in advance
@PositiveLeadDiagnostics6 жыл бұрын
That is pretty weird. What kind of vehicle?
@MrAndresinibus6 жыл бұрын
Positive Lead Diagnostics 2003 new beetle 1.8t with stick shift if it matters
@MrAndresinibus6 жыл бұрын
So I ordered a new regulator and now it's working like it should staying at around 13.5v n dropping to 13v with all loads on lights fog lights radio and A/C
@ramongumbs68046 жыл бұрын
Hi there i have a voltwagen cc 2.0t 2010 luxury i have a code p0658 actuator power supply A and P2257 and p 0491 u0101 i check all the selonoid in the tcm module and they 're okay
@stephanrosty19246 жыл бұрын
could you named this 4 wires to me thanx in advance
@aymenbouzouita89565 жыл бұрын
So what is the wire between the ECM and the alternator ?
@PositiveLeadDiagnostics5 жыл бұрын
Monitored circuit by the ecm. I think I misspoke in the video. There is no control from the ecm to the alternator. It’s only monitored
@aymenbouzouita89565 жыл бұрын
In the new génération of VW there is just 2 wires connected to the alternator, 1 coming from the ECM and the other coming from the Electronic central, which one control the alternator ? I unpluged it in a Golf 6 with a petrol engine and start tge car, nothing happened, no battery light and the car still charging
@PositiveLeadDiagnostics5 жыл бұрын
1 wire controls the dash light (battery). The other is monitored by the ecm. Nothing controls the alternator. It is a self-exciting alternator
@aymenbouzouita89565 жыл бұрын
The batterie indicator is in the screen, there is no bulb when I put the ignition, I start the car and unplug the 2 pins connector of the alternator and nothing happened, and when I unplug the fuse of the terminal battery to the alternator, the indicator of the battery light on the dash, I think the PCM monitor the voltage when it down to 12v when the engine is start, they send an information to the dash with CAN, I'm not sure but I think that
@PositiveLeadDiagnostics5 жыл бұрын
What’s the problem with the vehicle?
@Xomanowar994 жыл бұрын
Stupid putting the buld in series. They should put a resistor in parallel next to buld just in case the buld goes out.
@garyfischer53355 жыл бұрын
After reading some of the comments posted,,,It's a wonder why people post how to videos..........Way to many critics out there. #1 Cochran.....Pgh Guy...Me to !
@PositiveLeadDiagnostics5 жыл бұрын
Lol I agree. Oh well One thing is you will always learn when working on cars. There’s always one that will humble you. Which Cochran?
@garyfischer53355 жыл бұрын
It would appear to be Cochran VW
@frap67906 жыл бұрын
Bump the idle up and ship it! Haha 😂
@dudleyflodeen64286 жыл бұрын
Here’s what I know2011 Jetta 2.5 alt not charge charges on a bench test put a new one in it also test good on bench test main fuse was blown previous owner put a jumper wire across fuse wire melted we replaced the fuse still not charging the number 2 wires that go to the alternator the number 1 wire is giving me 12 volts number 2 is giving me 11 volts neither will light a test light the battery light blinks as does my meter goes 0 to 12 when car is running
@fluevano23162 жыл бұрын
hi same problem here were u able to fix the problem ..thanks
@Gagik57796 жыл бұрын
Bro it is self excited after 2500 prm I am sure you had don it for a 5 minutes ,video absolutly for auidience
@throttlebottle59066 жыл бұрын
harsh, maybe he's never ran into that before ;)
@tcifusion44976 жыл бұрын
000979133EA 2 SHOULD BE OK.FIX ALL 4 OF THEM......
@dubsydubs52346 жыл бұрын
Typical fault. broken excite circuit.
@haywardsautomotive61566 жыл бұрын
You're going to love the Pico Tom...good investment and the detail is great. Great video, diagnosis & repair Tom!!