Battery Light On

**OldYella** · 04-14-2008 08:18 PM

My battery light came on today and so i went home and parked it. Ive been searching all over as to what exactly is wrong. After the battery light came on on the speedo a few mins later the big orangeish screen put up the battery warning light and started yelling at me. I figured i had thrown the accessory belt at this point because the rest of the dash lit up like a Christmas tree. The TC light, the brake light flashing, and there is one or two more lights im forgetting.

So i killed the radio and turned off the lights in hopes of making it home. The tach and the speedo gauge were both dead by this time, window switches wouldnt work. Got home and parked it.

Brought out a volt meter and tested volts off 12.5 or so and 14 when at idle. Battery light still on when i was testing. So i decided to try to drive it down to autozone to have them check the battery and alternator. Got 2 blocks away and looked at the volt gauge and it was reading 16. Christmas tree was on the instrument cluster again. I played around with it a lil and when coasting at idle it was normal at 14volts. When in gear it was at 16.

Took it home after stopping for gas and it read high with the christmas tree effect intermittent depending on throttle position. Finally settled down and for the rest of the drive read low (12v) and seemed to slowly begin to drain. When i got home it must have been at 11 or so no lights but the battery light.

Anyways if youve read this far what is it? Is it the voltage regulator, the whole alternator, the battery, or could this be the ABS module?

Another question do the S4's have the voltage reg built into the alternator or are they connected but separate?

What kind of alternator did the S4's come with? I read that the A4's came with Bosch and Valeo, is that true with the S4's as well?

Sorry for the long winded post, i had driven the car for 3 days between it being down for the wheel bearing.

TIA

Andy

**mholme** · 04-14-2008 08:29 PM

Sounds like what happened to me when my alternator was dying. Get it tested if you can, drive up to advance auto with a jumper box.. My voltage would go up and down before it finally died, but the red battery light stayed on even after replacing the battery. Early ones had Valeo, later had Bosch, but you still want to verify which one you have.

**OldYella** · 04-15-2008 05:47 PM

ttt so is it the alternator or can i get away with just the volt regulator?

**ny02s4** · 04-15-2008 05:49 PM

def sounds like your alternator is on its way out.

**mholme** · 04-15-2008 06:02 PM

Originally Posted by OldYella

ttt so is it the alternator or can i get away with just the volt regulator?

Last time I checked, it wasn't worth doing the voltage regulator alone, I think the brushes/regulator was over 100 dollars. I just went with a reman Valeo. Depending on which one you have, your options may vary..