Quinn Campbell

I have a 2005 A4 3.0 Quattro that is having a bit of an issue. The battery icon (generator fault indicator) is coming on and off. I checked the voltage with my voltmeter and had the battery and alternator checked at O'Reilly's (in car) and everything checked out ok.

The light seems to come on and off while hitting bumps in the road (Chicago's got plenty of them), stays on more then off but has gone off for a few minutes only to come back on after another jossle.

Some extra details: car cranks up fine, Battery is about 2 years old, car sat for a few weeks/hadn't been driven much recently as I was out of town and it's motorcycle weather. Never had an electrical problem previously. 115k on clock.

From my searches and my assumption there's a frayed/damaged/split wire somewhere. Would anyone be able to point me in the best direct to start looking?

turbo510

I'd rig up a Voltmeter, say to the 12V accessory outlet between the front seats, so you can see what the Voltage is when the light comes on. If without the battery icon lit, the voltage is around 14, then the light comes on and voltage drops to 12-something, that would be clear evidence that the charging system has an intermittent fault. I'd suggest starting with the (hard to reach) connections on the back of the alternator.

Quinn Campbell

So the light is on more often then not, but even with it on I got a good reading at O'Reilly's? Should I still do the test hook up?

And you're saying the wires I should be looking for splits/damage are on the alt? Anywhere else you'd recommend, while down there with the skid plate off?

Thanks for the response

turbo510

I'd still rig the voltmeter, because the charge light may have a delay so it doesn't flicker, but latches on even when the voltage is back to normal. I just don't know so I would want to see an actual meter reading.

I wouldn't expect damaged wires, but maybe a connection problem due to corrosion, for instance. You would need to remove the connector to make sure the contacts were good, but remember to have the battery disconnected before dealing with the alternator.

Quinn Campbell

Driving the car today the alternator light was flickering as it had been until I ran over a bar section of Chicago street, then stayed off. Decided it was time to look at, since I needed to change my oil anyway.
what I found:
So there's a blue wire that attaches to the alternator (front right corner of the car). It was stripped and broken. I suspect that the bouncing finally tore it.


To fix I disassemble the plug (pictures and details below), tried to pry open the internal connector but couldn't. I instead removed as much old wire as possible, wrapped enough around the connector and soldered in place, reassembled everything and plugged back in.

​​​​​​Turned on the car and no light. So the mystery remains, why was the light on to begin with? It was completely severed and the light was off. It's been fixed and the light of off. Anyone got a guess?


Plug housing
Broken/work alternator generator wire
Plug location Audi a4 b6 3.0 alternator
Plug components. The orange is a squishy gasket, the purple a retaining clip. The purple is removed first from the side, not the end hole.orange will come out the end hole.
Plug housing 2nd view
Plug housing 3rd view
Plug housing 4thview
Internal wire, to remove I pulled from outside the housing. If you notice there is only 1 wing, used to be two, one broke off after removal when I folded them back into original direction. The wings are retention mechanism. You may be able to depressing the wings while still assembled through the housing. I was impatient and couldn't get it.
At the back end of the housing is a blue gasket around the wire. Waterproofing measure. It will come out when you pull the wire.