Random Battery Light : ON

[SN95Audi87]

Turned on my car today when I was in the parking deck at school, and the battery light was on. Looked at the voltage guage to the right of the dash to see it was not at the regular 14 volt mark. The car fired up fast and normal, but was right under the 12 volt mark. It declined a little while driving, but all of a sudden it reached 14 volts when I was driving up a steep hill around 3K RPM's, the light turned off and everything went back to normal.

After I came back from the depositing some cash from the bank, the battery light came back on and did the same exact scenario when I was at school. The previous owner told me the alternator was a remanufactured unit. I tested the battery with a multimeter and it was showing a consistent 11.92 Volts so the battery is healthy. I hope my alternator is not going south because it was replaced from what I was told.

From what I read on here. It could be a voltage regulator, brushes could be shot, or bad connection of some sort. Can someone point me in the right direction. To tell you the truth I hate remanufactured alternators but it seems like you cant buy new ones anymore.

[dumpedb5]

I am having a similar problem, I believe it is either a bad alternator or a bad connection.

[SN95Audi87]

I was looking on ebay, and in fact they do sell new ones, very ecstatic. Just not happy it happened now.

[SS92]

Replace your brushes if you have a valeo unit. Wally has a DIY. From what I read on here they go on stock units around 100k

[SN95Audi87]

I'll check to see if its a Valeo unit.

[Lapkritis]

Yes, voltage regualtor/brushes. Get a bosch unit; the generics have about 1/5th the life of the bosch unit due to cheap wear material.

[csosnowski]

meh, I put a duralast one on in place of a bosch over a year ago and its still going. 20k miles so far. $180+core.

Didnt really have a choice though, they were the only place in town with one for my car and its a DD and it was the weekend. Im happy with my choice, it works well, voltage never drops even with all of the accessories and lights on.

just throwin it out there.

EDIT: Just noticed this was the A4 section. My S had the alt let go, but when my A4's alt lets go Ill be sourcing the 120amp version from autozone as well, unless someone else has a better price.

[SN95Audi87]

Yes, voltage regualtor/brushes. Get a bosch unit; the generics have about 1/5th the life of the bosch unit due to cheap wear material.

Found a few people who are selling NEW not remanufactured units. I think I'm going to bite the bullet and just order them this week. I been down this road with my mustang so I absolutely dislike remanufactured parts because 70% of the time they fail.

[SN95Audi87]

Just doing an update for everyone. The alternator has a life of its own. One day it charges, One day it doesn't. Sometimes dont charge at all, and blink my eye its charging again. I have no idea what is going on with this thing. All I know re manufactured alternators blow lol.

[walky_talky20]

Mine did that and it was the rotor going open circuit. I got a Junkyard OEM Valeo for $35 and refreshed it with some new brushes for $5 and I was in business.

I don't do reman alternators. Want to know where they are rebuilt? I'll give you 1 guess.

[redline380]

sounds like a bad ground to me. id check all those first. might be a little cheaper. ive never experienced an alternator going bad like that. for me, when they go they just go. if it working and then not and then working again, i would look elsewhere

[SN95Audi87]

Mine did that and it was the rotor going open circuit. I got a Junkyard OEM Valeo for $35 and refreshed it with some new brushes for $5 and I was in business.

I don't do reman alternators. Want to know where they are rebuilt? I'll give you 1 guess.

I really do not know? where?

sounds like a bad ground to me. id check all those first. might be a little cheaper. ive never experienced an alternator going bad like that. for me, when they go they just go. if it working and then not and then working again, i would look elsewhere

where should I start looking? I only owned the car for a year so still new to things.

[trev718]

A year???
you shouuld be putting your hands all over it by now like a slut

[walky_talky20]

I really do not know? where?

You were supposed to guess...I thought I made this clear.

[redline380]

where should I start looking? I only owned the car for a year so still new to things.

id start at the negative post on the battery and then move onto any ground to the frame. i know theres one on the passenger side engine mount. after that im not positive but just look around for grounds to the frame. or wiresa on the alternator itself

[walky_talky20]

Yep, passenger side engine mount is the only engine ground point. A little pathetic, actually. I'm surprised there is not more problems due to that fact.

[Lapkritis]

A worn set of brushes will charge intermittently at first... often only at high rpm before failing completely.

[SN95Audi87]

A worn set of brushes will charge intermittently at first... often only at high rpm before failing completely.

It completely failed, doesn't even want to charge anymore. So I purchased this one. Hopefully it works great because I never want to replace this again. And again I severely dislike REMAN alts.

http://www.ebay.com/itm/290489664159...84.m1439.l2649

[walky_talky20]

Oh dear. That is a fully aftermarket unit (save the regulator). Good luck with that.

[SN95Audi87]

What's wrong with aftermarket units? I think a hand few of people on here got them on their cars from autozone, or your usual chain auto store. I was reading the reviews on the ebay store, and people are very confident with purchasing those alternators.

[walky_talky20]

It may well be fine for years. It is just the vast majority of aftermarket jazz is not up to the quality standards of the original equipment. This is why that new alternator is $150 and a genuine new unit is $800+. I'm all for the aftermarket stuff, but this is one of those items I'd much rather keep with the OE part. I do honestly wish you the best of luck with your ebay alternator.

[SN95Audi87]

It may well be fine for years. It is just the vast majority of aftermarket jazz is not up to the quality standards of the original equipment. This is why that new alternator is $150 and a genuine new unit is $800+. I'm all for the aftermarket stuff, but this is one of those items I'd much rather keep with the OE part. I do honestly wish you the best of luck with your ebay alternator.

I'll cross my fingers and hope I have never have a problem. But I have a OE remanufactured Valeo alternator that failed, so trying aftermarket stuff might not be as bad. What is a bad scenario, buying a OE Valeo Alternator or Bosch thats REMAN and it failing + paying a boatload of money for it. THAT SUCKS. Atleast I dont have crazy money into this one. We will just have to see.

[redline380]

Hopefully it works great because I never want to replace this again. And again I severely dislike REMAN alts.http://www.ebay.com/itm/290489664159...84.m1439.l2649

so why bother with crap if you dont wanna do it again? theres a reason half the stuff on our cars is bosch.

[SN95Audi87]

so why bother with crap if you dont wanna do it again? theres a reason half the stuff on our cars is bosch.

Bosch doesn't make alternators for audi! I got it in today looks to be a really nice piece. I'll update the thread when its on!