At what voltage does the battery light come on?

[aleccolin]

Just picked up an 01 6spd and if I can trust the voltage gauge it seems the alternator is on its way out. Charged fine 14 volts or so when I purchased it, now sits around 12.5 (just barely charging) cruising with no accessories; drops to below 12, maybe 11.5, with A/C, wipers, and headlights on. Previous owner said the battery had recently been replaced, which is a red flag, but since it was charging I had no reason to suspect the alternator.

I thought it was weird that I didn't get any sort of indicator light when it dropped to almost 11 volts.

I haven't really investigated yet, I'll get to it when the weather breaks. Hopefully it's just a connection, but that remains to be seen. I've checked out the manual to see what it takes to do the job. Not crazy about having to put the radiator support in "service position", but if that's what it takes.

Oh yeah, I don't have a radio code or VAG-com to reprogram all the convenience features when I disconnect the battery, does anyone know if you can use one of those 9V battery adapters that plugs into the cig. lighter to maintain memory on our cars?

[mholme]

I'd say to have the battery and the alternator tested first. It is strange that the alternator light isn't coming on when your battery voltage gets that low.

People have done it without going into service position...I don't see how, but they have..

Also, with the radio code, I've heard that if you power off the radio before you disconnect the battery, you won't need the code. I've never worried about doing it this way since I have my code. And your convenience features will relearn themselves(one touch windows).

[aleccolin]

I'd say to have the battery and the alternator tested first. It is strange that the alternator light isn't coming on when your battery voltage gets that low.

People have done it without going into service position...I don't see how, but they have..

Also, with the radio code, I've heard that if you power off the radio before you disconnect the battery, you won't need the code. I've never worried about doing it this way since I have my code. And your convenience features will relearn themselves(one touch windows).

Really? Can anyone confirm that, because it would really help to be able to disconnect the battery whenever I please without having to jump through hoops. If your radio does lock you out, can you use VAG-COM to get the code, or do you have to do that ahead of time?

[mholme]

Really? Can anyone confirm that, because it would really help to be able to disconnect the battery whenever I please without having to jump through hoops. If your radio does lock you out, can you use VAG-COM to get the code, or do you have to do that ahead of time?

You can't get it through VAG-COM. You have to pull the radio and give the dealer your VIN/AUZ numbers so they can look it up.

[aleccolin]

You can't get it through VAG-COM. You have to pull the radio and give the dealer your VIN/AUZ numbers so they can look it up.

Well, crap. How about the 9V memory keeper then? I've used them working at the parts store back in college, will they work with the S4, or is it some kind of trick switched cig lighter in them?

[mholme]

Well, crap. How about the 9V memory keeper then? I've used them working at the parts store back in college, will they work with the S4, or is it some kind of trick switched cig lighter in them?

If I had to guess, I'd say no, it won't work. But that's just a guess..

[aleccolin]

Okay, this is an excerpt from Ross-Tech's website (after the part where they say VAG Com won't/can't retrieve your radio code)

"In many cases, the radio will be in SAFE mode after disconnecting the battery, but it will automatically exit that mode after a period of time, as long as it is still installed in the same vehicle."

Anybody else heard of this, or have personal experience?

[1997gtx]

Check out the BOSE sticky. I believe this has been discussed :)
--Adam

[aleccolin]

Check out the BOSE sticky. I believe this has been discussed :)
--Adam

Thanks, I'll definitely check out some of those radio tweaks (esp. the eq) when I get my VAG-Com.

I'd still like to know, however, if simply unhooking the battery with the radio off, and hooking it back up when I have my alternator in will cause the radio to go into SAFE mode - and if so, will it relearn/reset itself after a period of time in the same car as Ross-Tech states?

[mholme]

Thanks, I'll definitely check out some of those radio tweaks (esp. the eq) when I get my VAG-Com.

I'd still like to know, however, if simply unhooking the battery with the radio off, and hooking it back up when I have my alternator in will cause the radio to go into SAFE mode - and if so, will it relearn/reset itself after a period of time in the same car as Ross-Tech states?

Only one way to find out...People swear it works, others say it doesn't..

I don't doubt what Ross-Tech says, but how long of a period of time do you have to wait is the question...I know it has to be longer than 24 hours..

[Matt@JHM]

Thanks, I'll definitely check out some of those radio tweaks (esp. the eq) when I get my VAG-Com.

I'd still like to know, however, if simply unhooking the battery with the radio off, and hooking it back up when I have my alternator in will cause the radio to go into SAFE mode - and if so, will it relearn/reset itself after a period of time in the same car as Ross-Tech states?

My radio was is SAFE mode for a week. It didn't unlock itself.

[aleccolin]

My radio was is SAFE mode for a week. It didn't unlock itself.

Do you remember if the radio was turned off before unhooking the battery?

[Matt@JHM]

Do you remember if the radio was turned off before unhooking the battery?

Nope.

[Rated S]

About the memory 9v things in the cigarette lighter, I know for a fact that Audi Dealerships use the solar panels to keep the batteries charged on lot cars, so I would 99% say that the 9v memory keeper will work as well.

[aleccolin]

About the memory 9v things in the cigarette lighter, I know for a fact that Audi Dealerships use the solar panels to keep the batteries charged on lot cars, so I would 99% say that the 9v memory keeper will work as well.

Wow, I'd never heard of that. I guess if the panels plug into the cig lighter then it'll work! I haven't had an opportunity to check, does the cig lighter work when the car is off, or is it always "hot". That'll answer the question right there.

Edit: Anybody know if there's a way to tell which alternator (Bosch or Valeo) I have without getting into the job?

[aleccolin]

Okay the sig lighter DOES stay energized all the time, so Rated S was exactly right I can use that. I figure I'll just wire a couple 6V dry cell batteries in series, tape them together, and throw a 12V accessory plug on the end. Should be enough power for a few days, probably a few weeks. I'll keep checking it with a meter to be sure.

Anybody know about the different alternators? It would be nice to know which one I need and just pick it up tomorrow instead of waiting until I have it all apart.

[mholme]

Okay the sig lighter DOES stay energized all the time, so Rated S was exactly right I can use that. I figure I'll just wire a couple 6V dry cell batteries in series, tape them together, and throw a 12V accessory plug on the end. Should be enough power for a few days, probably a few weeks. I'll keep checking it with a meter to be sure.

Anybody know about the different alternators? It would be nice to know which one I need and just pick it up tomorrow instead of waiting until I have it all apart.

He's right in theory..but like I said, only way to find out for sure is try it. And alternator types vary from year to year and the previous owner could have put anything in there if it was replaced in the past. You really need to crawl under the car and take a look to be 100 percent sure.

[aleccolin]

Update, found that previous owner or installer had used the spray corrosion inhibitor on the terminals. I hate that crap. Having worked at an auto parts store all through college I have seen how this stuff can get in-between the clamp and post and cause a bad connection, killing alternators and batteries alike. Sure enough, that had happened here. The battery was toast; I replaced it, dressed all the connections and put it back together. Charges on startup and idling in the garage, only time will tell if that stupid red shit - and the questionable connection resulting from it - has caused my alternator to give up the ghost as well as the battery.

BTW, I used my 1.5 amp slow charger and soldered a 12V accessory plug to one of the quick-disconnect leads that came with it and used that in the cigarette lighter to maintain 12V on the system while the battery was unplugged. This is a convenient way to keep a maintenance charge on a car in storage too, assuming the charger has a maintenance function built in so it won't over-charge. Curiously, this maintained memory on my stereo (thankfully) but I lost my one-tough up/down on the windows and probably some other stuff as well. I guess I'll have to figure out how to reprogram all that crap, but at least I don't have to pay the dealer for a radio code.

Anybody know where I can get a voltage regulator for this thing? I still don't know if it's a Valeo or Bosch alt. and I'm assuming it's an internal regulator, but the thing is charging, so if I need anything it's probably the regulator.

[mholme]

The one touch up/down feature will relearn itself on it's own

You need to get under there and look to see what kind of alternator you have. It's not hard to do. Just have plenty of light. The voltage regulator is almost as much as a reman. alternator...

[B501S4]

http://www.bimmerspecialist.com/usa/parts/index/audi has just about the best deal i know i had to do the same. mine was the bosch but your could either be the valeo or the bosch both are 120amp and at a better price then even my buddy at the dealership could get at shop prices

[aleccolin]

Okay, just going off the voltmeter in the dash:

Holds at or around 14V while driving with accessories and lights off. I'm happy with that.

Drops to approximately 13V, maybe a little less, at idle with accessories and lights off.

Drops to 12.5V with headlights on while driving. Just above 12 at idle with headlights on.

So the question is, what is the 'normal' voltage I should be seeing at idle and cruise with the headlights on? How much current do those things pull anyway? I think the lows are 55W each? At 12.5V that's only about 9A, then maybe another 5A for the rest of the lights. 14A shouldn't be pulling it down that low, but it does hold it so I don't know.

Probably going to stop at the parts store today and borrow their load tester.

Open to suggestions.

[The_Jerbel]

1. You should be at 13.8V regardless of how much crap you turn on, and ~14.2 with nothing on.

2. The auto windows up and down won't re-learn on their own. You need to hold each window switch down (or maybe it's up, I can't remember) for an entire second and it'll re-program.

3. '00 used Valeo, '01 and up used Bosch IIRC.

[aleccolin]

1. You should be at 13.8V regardless of how much crap you turn on, and ~14.2 with nothing on.

2. The auto windows up and down won't re-learn on their own. You need to hold each window switch down (or maybe it's up, I can't remember) for an entire second and it'll re-program.

3. '00 used Valeo, '01 and up used Bosch IIRC.

Okay thanks, I'll try the window thing later. I figured as much about the alternator/voltage regulator. I've seen some cars that had some variation, but not as much as I have. Sitting in traffic yesterday everything got good and hot and output continued to drop to the point that with headlights and A/C it was just below 12V. Not good. I guess I'll be investing in an alternator anyway.

[mholme]

2. The auto windows up and down won't re-learn on their own. You need to hold each window switch down (or maybe it's up, I can't remember) for an entire second and it'll re-program.

3. '00 used Valeo, '01 and up used Bosch IIRC.

2. An easier way for the windows: Put them all down, bring them all back up. The windows should now one touch down(and front doors up). Thta's what I meant by "relearn". I guess I should have been more specific.

3. It's still better to be safe than sorry and get under the car before ordering a new one, in my opinion. The previous owner(s) could have replaced it with whatever they got a hold of.

[The_Jerbel]

Yeah, it doesn't matter how you do the windows, the important thing is that you hold the switch down for 1 full second.

[alias747]

Is there a way to get the back windows to go UP with one touch? All 4 of my windows go down with 1 touch and the front ones go up with 1 touch, but the rear ones won't. Thanks!

[mholme]

Is there a way to get the back windows to go UP with one touch? All 4 of my windows go down with 1 touch and the front ones go up with 1 touch, but the rear ones won't. Thanks!

http://www.obdtool.com/onetouch/

[alias747]

http://www.obdtool.com/onetouch/

Lol thanks for the help but good lord there is no frickin way that I am going to invest that much time and effort to get my stupid windows to roll up by themselves... I don't even understand why Audi did that on the S4. My A6 had one touch up rear windows. Audi confuses me sometimes.

[mholme]

Lol thanks for the help but good lord there is no frickin way that I am going to invest that much time and effort to get my stupid windows to roll up by themselves... I don't even understand why Audi did that on the S4. My A6 had one touch up rear windows. Audi confuses me sometimes.

It's about a 30-45 minute job. Takes longer to change spark plugs than this project does..

[alias747]

It's about a 30-45 minute job. Takes longer to change spark plugs than this project does..

Yeah but I am still not going to rip my door apart to do something so trivial. When you change plugs you are at least accomplishing something somewhat important... lol

[aleccolin]

Yeah I'm not worried about one touch up on the rears. I rarely ever put them down to begin with, but it's a MUST for the fronts now that I've gotten used to it.

I'm not sure right now where to get a decent reman'd alternator. I'm definitely not buying one from Advance or Auto Zone given the complexity of changing this thing out. Napa maybe, has anybody had any luck with Bap Geon? I can't remember who their remanufacturer is (Talon maybe?) but I've been satisfied with everything else I've gotten from them. Import parts only, and they always know their stuff.