Now no alternator
 

So my 82 had a weak alternator, was giving 12.8v under load. Drove it 150 mi last night in the dark, ac headlights etc all were fine... This am, 11.8v. Alternator won't charge, no alt light at all...

Swapped bulbs, no dice.

Fortunately since it's a diesel and daylight I can drive home without - 11.8v operates brake and turn lights.

But what does it mean with no charge and no alt light?

First things I'd check is the voltage regulator. And that all your connections are tight.

I had the same problem last week. Alt not charging and alt light not coming up. This is what I did: I got a multimeter and a schematic of my charging system and tested the battery voltage with the engine off, on and at more or less 2000 RPM, same flat 12V every time. I checked to see if there was continuity from the alt to the battery, no continuity. I then checked every circuit to make sure that it wasn't some loose wire or a faulty bulb. I was told that if the bulb is shot the alt won't charge. Beats me why, but I checked it anyways. All my wiring checked out okay. So I ordered a new alternator online and it's on its way. I really made sure that it was the alternator that was faulty before ordering one.
I had charging problems a month before and it turned out to be the regulator. I'd check that too as it's cheaper and easier to install.

The free autozone test claims regulator. Would that keep the light from coming on?

Did they Test the Alternator while it was still on the Car or was it tested on a Bench.

If I had this issue I would have a preference for the Bench test because it eliminates any of the wiring/bad connector issues that also could cause the same problem.

Several of the Members have said when one or both of the Brushes on the Voltage Regulator were worn their Battery died and they saw no Battery Light go on.
If I remember correctly if the Brushes are worn 2MM or less they are no good.
I suppose the Brushes could be sticking out more and still not make contact if the Silp Ring was worn deep.

A little long winded but there is some info.
http://www.humanspeakers.com/audi/alternator.htm

Not bench - just on the car, I was 150 mi from home.

Will pull the EEG tonight and see, if it looks ok I'll pull the alt.

[QUOTE=cirrusman;2541558]I.... I checked to see if there was continuity from the alt to the battery, no continuity. .....QUOTE]

You need continuity from alternator to battery.

Well, found my issue... Put my car up on ramps when I got home (in the dark), after driving all the way home. That is what I love about diesels... I could drive my battery down to 9V (granted it is likely ruined, I have it charging), no alternator, and make a 150 mile drive home. Try doing that with a gasser...

Anyway, wanted to pull my voltage regulator to get a feel for the brushes and what was going on there. As soon as I unscrewed the screws and pulled it out, one brush fell out. It felt as if there wasnt even a wire in the insulation for the connecting wire for the brush...

The one was also worn funny compared to the other.

http://i83.photobucket.com/albums/j3...2/IMG_2439.jpg

http://i83.photobucket.com/albums/j3...2/IMG_2440.jpg

So I need to get a new regulator and then hopefully all is well. I am going to try the Altrom / Beru brand from Napa (their prices on regulators are horrid) instead of bosch because the beru is a 14.2V regulator versus the bosch at 14. Given my experience with these older cars and what the bosch alternators put out (my 91 BMW included) a slightly higher regulator helps keep the battery better charged.

Dont throw that old reg out. It probably only needs new brushes. solder new brushes in & keep it for when the new reg fails.

Yeah,I Know, that's why I ordered a new alternator... :)

I had exactly the same problem about a year ago. The alternator light/battery light on the instrument cluster is not coming on when I turn the ignition key to ON position, and at the same time, my battery is draining which means the alternator is not charging the battery. The bulb is good, the fuse is good, the voltage regulator is good, and the overvoltage protection relay fuse is also good. I finally replaced the alternator and fixed the problem. I had that old alternator bench-tested at AutoZone and their tester determined that the alternator diodes are bad.

Yeah I learned that diode lesson on my BMW a few years back...

I also have experenced this: worn brushes = no charge and no alt light.

The first time my TE stranded me, when about 4 years old.