Alt not charging, failed test at shop

[wolfsburged]

'84 Jetta TD w/ AC. I have a Bosch reman alternator that is less than 2 years old. Was in Georgia for the weekend when tach started acting erratic and then died (Dakota Digital run off of w-terminal). Battery light on dash came on dim at first and then solid. Drove 360 miles home this way, battery voltage at first was around 14V and then dropped to about 11V at the end. Checked belt tension, seemed OK.

Got the alternator off tonight and took it to Advance Auto who ran it on their tester. Here are the results:

Tester Energize Volts Result: Pass
Key-on/Engine-off Volts 12.2
Voltage Set Point 12.3

Light Circuit Result: Pass
Key-on/engine-off light volts: 2.2
Engine running light volts: 0

DC Volts result - Fail
Output: 0

So my question is: Does this sound like a voltage regulator issue? I'm thinking of replacing it regardless to see as it is cheaper than a whole new alternator. Alternator spins fine, makes no bad noises, no shaft play. Pulled the voltage regulator and don't see any excessive brush wear.

Also, I see Bosch, Hella, and Huco/KAE as suppliers, any preference? Bosch is most expensive (best?).

[ORCoaster]

What is the cost difference between replacing the voltage regulator and replacing the alternator?  One gets you a solid fix the other might just be a waste of your dime.  If the test fails I would look into a warrantied replacement for the alternator.  Why fool with it any other way.  Pay the man and drive in confidence and a full up battery.

[bajacalal]

Because the voltage regulator on these alternators is Bosch type alternators is so easy to change (it takes all of about a minute, it's two screws on the back of the alternator and the brushes come along with it) I carry an extra one in my glove box. I would just get another regulator and see what it does. If it's not the regulator, you have one for a spare. I have found them between $20-40. Or you could find a few at the junkyard for a couple bucks each and give them a try.

[wolfsburged]

I am just wondering if these regulators are a known weak point, I mean that seems like the majority of the actual possible wear items. I can't imagine aside from bearings wearing out that the windings of the alternator are likely to fail.

Cost of alternator is 2-3x that of a regulator. I will probably try the regulator first and if its not, then I will have a spare to carry.

[ORCoaster]

go for it.  A spare is not a bad thing to have.  Better than packing a honking alternator around.

[bajacalal]

I can't imagine the windings being "bad" either, but maybe shorted or something like that. Also, the regulator has a weird way of connecting with the alternator internals by pressing on some spring loaded contacts in there, I bet those could corrode of lose tension.

[745 turbogreasel]

I had to  clean  my alternator inside before the fresh brush pack would work.
Hows $12? http://cgi.ebay.com/ebaymotors/VW-Audi-Bosch-alternator-brush-kit-new-0-192-052-004-_W0QQcmdZViewItemQQ_trkparmsZalgoQ3dSIQ26itsQ3dIQ26ituQ3dUCIQ252BUAQ252BFICSQ26otnQ3d21Q26pmodQ3d130455435495Q26psQ3d54QQ_trksidZp3284Q2em263QQitemZ200611218360

[damac]

I had my jetta almost a year now and all of a sudden last week it stopped charging and I didn't notice until it wouldn't start one day

I looked over things and checked the circuits in the dash like people here said to do and that all checked out, led good, etc.

I didn't have spares so just decided it would be more cost effective to pay autozone $80+tax for one of their alternators with a limited lifetime warranty.  I have to return the core but for a car I plan to drive a long time I have to wonder if this isn't the best route to take??? 

I could have bought a used one for half the price if I am lucky but then no warranty and with my luck something else would die a week later

I have to wonder about autozones quality but then again it will be easy to change out in a parking lot, they have lots of stores, and if you pay attention to your car I don't think you should get stuck at the point of failure if you can keep the lights and stuff off and keep the car running

My unit looks brand new.  Only thing I noticed at first glance is the lower terminal isn't a ring so I will have to change the wire end from dash to a spade.

Tomorrow I will find out how easy it is to swap the pulley over, the new one doesn't include anything but a nut.

[damac]

I just finished mine and things are working again atleast during my short testing

The autozone alternator they show on their website for my 85 turbo diesel with no ac has the older style connectors, looking for a plug that goes into the alternator.

So I had to hack my connections and install spade stuff the best I could with local parts.  The d terminal sits next to 2 larger b terminals.

Unlike the directions mentioned in the box, mine came with a suppressor and a voltage regulator which are external like my old regulator.  It had a new nut and lock washer.

I took my old alternator apart and everything swapped over ok, was surprised to see how easy I could break the nut and found that although every piece was slotted for a keyway, there was none installed, so I just let it be and transferred everything over.

[BigVWman]

The regulator is your weakest point and its where i would start. Windings and armatures almost never go bad and diodes occasionally but then you loose portions of charging capacity. I would install a new set of regulator/brush's long before i installed a "reman" or rebuilt autozone unit. The bosch you have is probably longer lasting in the long run. Some of those reman autozone/advanced alts and starters are downright scary sad. My piece of ind is not having to mess with it even if there are many autozones around for warranty service.

[bajacalal]

Aren't Autozone alternators rebuilt somewhere like Malaysia lol?

That said, it isn't that hard to rebuild most alternators. Seriously, try it sometime. It surprises me that doing so isn't more common.

I worked at a Napa auto parts store years ago and we sold 3 brands for rebuilt electrical stuff- Bosch, Cardone and some no-name local company that nobody has ever heard of called BBB Industries which were usually the cheapest.

Surprisingly, the Bosch ones seemed to be the worst, people returned them for warranty in less that an week, at least 50% of the time, followed by Cardone in which maybe 1 in 10 was defective and that company nobody has ever heard of was actually really good, those hardly ever came back. I've used their stuff myself with no problems. I've heard Bosch Remanufactured is some sort of separate entity than new Bosch stuff and doesn't have great quality control.

[BigVWman]

Rebuilding alt's and starters is easy super easy unless windings or armatures go bad. The biggest problem the DIY's have right now is finding the parts to rebuild them!Except maybe online and when you need the car tomorrow that won't help! Where as my fav import supplier used to stock voltage regulators and brush's, he's gone and I haven't found a replacement supplier. I don't think auto zone or advanced alts and starters are rebuilt in one place. I have tried them and 3 for 3 failed or had issues right out of the box, one i even disassembled and fixed myself since i knew it was the only game in town and they were the only ones dumb enough to take a reg rabbit starter as a core on a tdi starter. Bosch i am 2 for 2 successful and one of those has over 100k on it now, your experience may differ. The rest i have rebuilt myself.

[Vangruver]

Have you had a chance to check the exciter wire to the battery terminal?

it's a blue wire that is on the body of the alternator.

I just had the same problem with mine, battery light however was flickering and turning on and off repeatedly. Checked the voltage reg, that was fresh and checked the voltage coming off the alternator that was good, can't check the amperage, however i suspect it should be alright. Checked the excitor wire and found that it was barely holding on by a copper strand, replaced the lead and it's a success.

[ORCoaster]

Checked the exciter wire and found that it was barely holding on by a copper strand, replaced the lead and it's a success.

Is this loose wire the reason some of us have that flicker of the ignition light at idle?  I have reinforced the ground from the alt to the block and it still seems to do it after a long drive.  Have you heard of a fix other that securing the two ends of the wires?

Only does it at idle after a 4 hour drive.  Real faint flicker that can only be seen in the dark of night.

[Vangruver]

Checked the exciter wire and found that it was barely holding on by a copper strand, replaced the lead and it's a success.

Is this loose wire the reason some of us have that flicker of the ignition light at idle?  I have reinforced the ground from the alt to the block and it still seems to do it after a long drive.  Have you heard of a fix other that securing the two ends of the wires?

Only does it at idle after a 4 hour drive.  Real faint flicker that can only be seen in the dark of night.

I can't guarantee the wire is the sole cause of all the flickering light problems, but it is the lead that sends a signal to the alternator to start operating, or the cause for it to create its load. Upon a certain rpm, or voltage spike (example blipping the throttle from start) the blue excitor wire will then turn the alternator on to start creation of voltage to the remainder of the system, to reduce draw from the battery.

Check the lead just to be sure, its located on the body of the alt, and mounted on mine with a 6mm fastener