Intermittent flashing battery light

[Mike02A4]

I started getting this on my way in to work this morning and on my way home. Its intermittent, just kinda comes on for a second then goes off, not steady on. I just charged up the battery so i'll see if it comes back on. I guess my next thing to do is have autozone load test the system. This should give me a definate answer as to if its the battery or the alternator, correct? Its an 02 a4 1.8t.

[mtbrider]

Is this the battery sign that pops up where the radio station info would be on the dash? I'm having the same problem and after three batteries I'm finally changing my alternator. Hopefully this is the fix.

[Mike02A4]

Its a little red battery symbol on the gauge cluster, just outside the 'box' where the radio station stuff is..

[Mike02A4]

hi?

[old guy]

hi?

Get a multi-meter and check your battery output. Fully charged it should be around 12.6 V. with the car running it should be charging around 13.5 V to 14.1 V. If not you may need a new alternator.

Edit: And if you don't have a multimeter I recommend this one: Friggin' thing is awesome!! Clicky click It even has a built in IR scanner!

[Mike02A4]

It was 12.55v when I checked it. I recharged it yesterday afternoon and drove it but the light never came back on. I have not checked it with the meter since charging it. I will try that tomorrow both on and off. An alternator job looks like a bitch on these cars..

I wonder since I do a lot of short trip local driving, that that could not let the battery fully charge?

[T0M3K]

I had the same problem, good alternator, good battery, ended up being cut control wire from alternator. Retapped and problem solved (after weeks of bothering me)

[trueno429]

ur alternator is goin bad..

[old guy]

It was 12.55v when I checked it. I recharged it yesterday afternoon and drove it but the light never came back on. I have not checked it with the meter since charging it. I will try that tomorrow both on and off. An alternator job looks like a bitch on these cars..

I wonder since I do a lot of short trip local driving, that that could not let the battery fully charge?

If it checked at 12.55v it sounds like the battery is OK. Be sure to check the output while the motor is running. A low battery usually won't give you a warning light. A faulty alternator will. Also be sure to check the belt tensioner on the serpentine belt to make sure the belt isn't slipping.

Good luck!

[Mike02A4]

I will do a running volt test tomorrow. I checked the belt and its tight. How tough of a job is the alternator?

[old guy]

I will do a running volt test tomorrow. I checked the belt and its tight. How tough of a job is the alternator?

Not too bad. You can use the first part of this DIY to see what it entails: Clicky click

[Mike02A4]

Here are my Volt readings..

Car on: 14.1v
Car on with a/c on full blast and headlights on: 13.3v

Whatcha think?

[old guy]

Here are my Volt readings..

Car on: 14.1v
Car on with a/c on full blast and headlights on: 13.3v

Whatcha think?

It sounds like the alternator is working properly. Is the light still coming on?

[Mike02A4]

No the light hasn't come on since I charged the battery saturday afternoon.

[grimlock]

I've had the exact same problem for the past couple of weeks. The flashing actually seems to correlate to when I hit bumps in the road. This leads me to believe that it is most likely some sort of wiring issue somewhere, probably just a wire that needs to be retapped or replaced. I haven't experienced any issues as far as performance or functionality is concerned.

[n7plus1]

do you have a heatshield from matt?

[grimlock]

As a matter of fact I do! Is that what the cause is?

[n7plus1]

As a matter of fact I do! Is that what the cause is?

yea...its rubbing through a wire at the bottom of the heatshield...the one thats steel braided...left, next to the turbo/exhaust. This is causing a short and making the light go off. I have the same problem and need to figure out how to fix it. I knew EXACTLY what your talking about with the bumps in the road setting it off, etc. Arent you glad i chimed in?

[grimlock]

yea...its rubbing through a wire at the bottom of the heatshield...the one thats steel braided...left, next to the turbo/exhaust. This is causing a short and making the light go off. I have the same problem and need to figure out how to fix it. I knew EXACTLY what your talking about with the bumps in the road setting it off, etc. Arent you glad i chimed in?

Haha, definitely. Saves me from going on a wild goose chase! If it's the bottom of the heatshield that's rubbing, what about just wrapping a strip of electrical tape on the bottom edge, would that work?

[n7plus1]

Haha, definitely. Saves me from going on a wild goose chase! If it's the bottom of the heatshield that's rubbing, what about just wrapping a strip of electrical tape on the bottom edge, would that work?

sure, until it rubs through that...im not sure what i want to do yet...i might try to relocate the wiring..or cover it with something else.

[BNZ TOY]

Not too bad. You can use the first part of this DIY to see what it entails: Clicky click

always nice to see the "Clicky click" again

[dirtybrd]

sure, until it rubs through that...im not sure what i want to do yet...i might try to relocate the wiring..or cover it with something else.

Just trim the heatshield until it clears the harness.

[Mike02A4]

I just checked my voltage and it was a little lower than it was this afternoon. It was 13.9V at idle. Normal for it to be lower or am i just being paranoid? I also heard some sort of random clickign noise comming from the alternator area. It was random and intermittent. The low battery light has NOT came back on yet..

[Dazm89]

I'm super lost here folks. I have an 03 1.8t quattro 5 speed manual. Have a good battery tested with multimeter at 12.55. Replaced the alternator and starter 2 days ago. Alternator reads 13.82. I'll be posting this in the no start thread as well because it won't start. There's an upgraded head unit to give bluetooth connectivity to the factory Bose sound system. The ground wires have all been replaced as well as power from alternator to battery and battery to starter. Now on top of not starting the battery light is flashing. A push start works and it runs but this is killing me. Help