VW A4: Intermittent Low Charging Voltage 

Quick find on the bad connection Thomas and good demonstration of voltage drop.

I checked my car for this same problem sure enough same thing was so hot it burnt my finger. I took apart the whole fuse holder and cleaned up all the metal parts. Alternator wire where it connects to fuse had some brown junk on it somehow couldn't see it till you removed it. It still gets warm but 81f vs burning my finger was 131f right after starting. This vid saved my fuseholder from meltdown lol.

Excellent video Thomas.. Great use of the temp gun to show viewers what you were doing. Always learning something new from your videos.

I have same problem with my skoda fabia 1.2 12v red light of battery 2 days... I clean all 5 plank and everything is fine tmx you again !!!

Love the way you film and edit videos, Very clean and professional Will subscribe to your series. Very helpful and a reminder that small electrical faults can cause much larger issues. PROPS!

It's not the fuse box on these cars that is the problem, it's the crimp connection on the black wire. The problem is VW has a special 7 mm connector nut on the end of their alternator wire where it connects to the fuse box, the regular copper connection are too wide to fit in the little groves in the fuse box. I just ended up making a connection out of 1/4 inch copper pipe. It worked out better than what they had from the factory. They just undersized the fitting on this job.

Wish I would have found this video after hours of trying to figure out WTF was wrong with my Jetta--it wasn't charging. Crimped that connection down more, soldered it, and, BAM, it now charges perfectly.

The problem lies in the black cable from the alternator to the fuse box at the end it has a nut stock from factory which in time gets electrical resistance cut behind nut clean up wire and put new crimp on it and your set to go

Such a simple trick saved me 30 $ on a new diode / rectififer kit...

my voltage when engine run about 13.7v to 13.8v. is this normal? also got issue with my car rough running & sometime stall when the epc light up. New throttle body has been replaced recently but the issue seem to be still there but it comes intermittently. Which I presume its voltage related and I need to check just like you did in the video.

Classic example of friction bond failures compared to welds or solders.

my 2008 Tiguan puttiing out 13.6V when engine running, see your video I might look into it soon. thanks

if the wiring checks out , could it be a faulty regulator on the alternator?

Dude, you are my hero!! Had the same issue and fixed it by watching this video. Didn't have the fancy snap-on VOM but got the job done. What's the normal running voltage for these cars? I have the heater fan on 2, my stereo was powered up but not playing (amp in trunk was on, aftermarket) and i'm getting steady 14v. Headlights on I get ~13.8v. I am running ballasts with HID's. Should I be looking at a replacement alternator soon? It's a 2003 VW GTI 20th with original alternator.

I change the alternator for my car and it is stilll giving me 13V and idk what I got and Audi A4 2009 I really need someone to help me

Thank you for the video. I have the same issue with a 2010 Vw Golf.

Thank you very much for this super informative video!

Great video, as are all of yours! I really appreciate you're making these. I've learned a ton from your videos, even though I only very recently came to appreciate what a stud my "2.slow" VW is and how great the VW community is and how much I can do myself! I've got a Mk4 Jetta Wagen (AVH engine code) and I'm getting a misfire on Cyl 1 (according to my recently procured VCDS setup... holy crap, do other brands have such an amazing tool?), but only when I have accessories running. My voltage drop from battery + to Alternator stud is 0.1 or so with no accessories on, but jumps to 0.3 or sometimes higher with accessories on. The alternator cable, likewise, heats up like crazy with accessories on (I wish I had an IR thermometer like you, I know the old fashioned way... ouch!). Could a bad wire from battery to alternator cause a misfire like this? When I get the misfiring (again, only when accessories are on), I can also hear an arcing/snapping sound coming from around cylinder one, but I never see an arc. I had recently changed the coil pack and spark plug wires as I had an overheat due to exploding coolant from a long overdue coolant flange and was running like crap. My #2 and #3 wires had out of spec resistances. (When I was in doing the wires, I also changed the spark plugs. ) Since I had a good (as far as resistance goes) #1 spark plug wire, I pulled the new OEM #1 wire out and put the older NGK wire back in, but the problem did not change. I pulled the battery and tray out and cleaned up all of my grounds under there, just to be sure they were good (though my voltage drop testing on ground side seemed fine... max was about .1 V when checking various grounds, though I didn't check the ground in the plenum for the ECU (I can't get my wiper blade arms off for the life of me). Sorry if this is too much information!

I was the owner of a beetle, long history, anyway I would suggest to get this problem fix and get rid of that money pit car, a saw this same problem over and over again on those vw cars, even on new models

Thank you for sharing your knowledge. Do you need to replace that entire fuse box or just the 150A fuse?

I have electrical engineer problem the door locks on and off

Oh by the way is a 2008 Volkswagen Jetta 2.5 it turns on when I drive it for a while he shuts off when I play around with a few box and when I go to turn it on it turns on why is that

Well done,interesting thought process - the temp gun- bang on Thomas- TST says too many techs don't know how to do a voltage drop - not - well you did it in under 30 sec. Thomas does the shop provide the Vantage or is it yours ?

Great video! thanks!

Why is temporary when you cleaned fuse and connector ? Is there better solution ? Btw thank you for video !

I have VW golf 1.4 tsi automatic . Car start but after gear in drive car not running and computer shows error System voltage low Kindly help

creo que jsto sea lo que pasa a mi audi tt ,,solo que mi audi tt ni se pone eb marcha solo si desconcto bateria y vuelvo a conectar despue de 15minutos es que se pone en marcha pero si le paro no vuelve a andar

Excellent video .

I have a question about if a alternator from a 1999 v w passatwill work in a 2011Volkswagon Tiguan SEl 4 motion navigation system

nice video! I have a question - have you ever had a case where the charging voltage is around 14 after cold start and drops to around 13 when warm?

Thanks for this. 2001 Beetle suddenly throwing p0562 CEL after swapping out the fuse box. A bit surprising because I decided to buy the most expensive fuse box on Rock Auto thinking I'd get higher quality than the super cheap one it's replacing. The super cheap one didn't survive my son putting the jumper cables on backwards. Had the original VW fuse box in there while waiting for the Rock Auto part and had no CEL issue, but the original has the floppy A/C fuse slot issue. This design is something I don't care for. Do you have a non-OEM fuse box you would recommend or do you only use OEM fuse box? 2001New Beetle.

Nice work, my 1999 Toyota Avalon when I crack it on read on multimeter 13.75 without accessory on and keep dropping voltages from 13.75, 13.74, 13.73 down even 12, voltage to battery low, I don't where to look at

I think I may be having this same issue on my GTI. I’m experiencing low voltage but my battery has never died on me. Everything in my car works fine however since I have LED brake lights installed they need full voltage to function properly and so they are flickering. Ram my codes and got a 01314.

Thomas I have a new alternator and when I start the engine first time when a its cold my alternator warning comes up and after letting run the engine couple of minutes and worm up in this whole time its running on battery not charging at all, after I stop the engine and start again I have 14.4 charging like never happened anything, my battery its a little weak anyway but shouldn happen like this, sometimes doesn't happen when it's cold only after I activate heated mirrors and rear window. The same issue I had with old alternator wich tested on another car and works perfectly

That's why i hate VW I remember having issues with that stupid fuse box in the past, in summer always get fried because too much heat on the wires.

Bro what is most coomon in golf 4 parazitic drain ?? I have my car batery drains when i park more 2 hours

I have a 2008 Volkswagen Jetta I noticed that my car shuts off when I’m driving when I check the fuel box and move it around and then when I go to turn on the car it turns on why is that

I have an 03 audi a4 and i got a code P1696 AUDI - CAN Data Bus Steering Column Electronics Incorrect Signal And its showin another code for low voltage. Whats the first thing to look at

I have similar issue with my 2006 gti I clean all the connections in the fuse box and keeps doing the same when is at idle reads 12 v and if I rev the engine it goes up to 14 v and I can be driving around with no issues.. any thoughts?

Hi Thomas. First of all your video is very good. I had/have the same problem. Because of melted plastic the alternator don't charged the battery. That was one year earlier. Then a friend helped me and cleaned the copper ring. The problem was solved....for the moment. This year when I turned on the air conditioning, I felt that the car was out of power, when I don't accelerate I had the feeling that I press the break. Without AC started the car behaved normally. After this I stopped the car and I checked that black cable from the fuse box,...that was hot and when I put the wrench to squeeze it, I saw that 110A fuse was broked. I changed the fuse box with a new one, I cleaned the connections, but that black cable is unchanged hot (I don't know what temperature have the cable termination but when I check with my finger I resist 2sec). Can the problem be elsewhere? With an OBD2 bluetooth tester I measured 14,1V Until now the new fuse box it's ok, but maybe later will be melted too. What can be the problem? Can you help me?

I have a 04 Passat that's not getting any fire! And throwing up every code there is! Any suggestions? Thank's

Was this causing parasitic draw?? My 1.8 gti golf has 650 mA of parasitic draw and I have no idea where to look

Your videos are amazing. Question... "alternator workshop" message pops on intermittently when aircon is on. It doesnt ever pop up if ac is off on Golf MK4. Can be fuse or any other problem?

I have jetta 2002 1.8t EPC light is on and car cuts off when I drive do you think is tensioner chain bad

Hi, I suddenly had 3 elective peobpemas. 1, my odometer shows no speed, my outside temperature sensor stopped at 11 degrees, my fuel level, even though it goes up and down in turns, then drops to 0. These errors occurred simultaneously. what do you think it could be?

I have a similar problem with a 2013 jetta tsi 2.5 I replaced the alternator 3 times every time I would switch it on it will stay on for 5 minutes then a battery light pops up and it losses voltage but I don’t know how please help me, Thanks.

Pls is this fault similar to power supply terminal 15 p1600 -35-10 voltage too low- intermittent. Pls how do fix this issue pls

My Ford Freestyle is reading low voltage....new starter, new alternator, new throttle body. I have no idea what to check next 🤦. Any suggestions?

is 14.1v to 14.01 ok charge rate?

My 99 beetle tdi has the battery light alluminated started a day ago. The other thing is it is doing something that feels like a vacuum issue. when you hit the brakes it starts to run rough. I have an obd and it throws a P0380 and P1403. Any help would be appreciated and thanks for the great videos.

Thanks so much !!!

Damn Germans and their plastics that melt and warp. That tray should be made of metal. smh

thomas i am geting a 17911 - Load Signal from Alternator Term. DF P1503 - 35-10 - Implausible Signal - Intermittent from VCDS, and when i start the car and remove the + terminal from the battery the engine switches off

I have done all of this and still my wires are getting very hot at the fuse box! I replaced the battery, the fuse box, the alternator wire and still getting really hot. Could my alternator cause them to heat up? I notice that my intrument panel gets dimmer when I roll up my windows.

Can you show this for an audi q7 4L pls?

very nice

I have a question do I have to get a 4 gauge cable and change the one black cable??

01598 vw fault code intermittente 000 salve ho questo codice golf 5 batteria nuova non riesco a venirne a vcapo sai dirmi qualcosa??

Did it end up being the alternator wire harness that needed to be replaced? I'm having low charging problems and need help lol

Awesome video. Am going to check this first as it's seems easier than my first plan.... Have a jetta where the alternator warning light comes on but ONLY when you accelerate hard. First thought was the belt on the alternator must be slipping under load and it seems a little loose. So maybe the tensioner... What do you think?

@thomasxovcds hey I change the alternator on a 2014 Audi A7 now I am not getting any power to the alternator can this be the fault?

I just got a jetta n think thats my problem there Im also a part time youtuber i was wondering what kind of camera do you use

hi could you let me know the shop Nam so I can bring my car in please ?

hey thomas its me again i know. vws. Ok so last week my battery light kept coming on and my car was losing cranking power with each crank, untill it would no longer crank. They said battery was bad. I replaced battery with new autozone gold battery. same thing was happening this week but this battery never really gave out untill today. i was driving then the airbag light and abs light came on. Then the radio turnd itself off. Then the epc light came on and the car was stuck at 2000 rpms, with power loss. Parked to the side. Turned it off and scanned. The epc light didnt return only battery light and cel. Code i got was P0030. Is the issue of all this the alternator ? oxygen sensor? ill check fuse box tommorrow. any help is great. Thanks

I was going to say why not just change the box? Cleaning it is a short term fix, then the temporary fix text popped up LOL.

El cable q pusiste hacia donde va conectado