Battery Light on after voltage regulator replacement.

[UrS6]

My mechanic claims it is a cluster issue and that it is charging ok. Dash and vagcom put it at around 14.1. Just got a new battery and VR. I just drove it for 2 hours at night and it must be charging because I'm not writing from the side of Route 128. Any thoughts? Or am I in the market for a new cluster?

[MaxRS6]

Seems like a strange coincidence. Less than .03 worth..

[lswing]

Can you clear a code and have it go away?

[UrS6]

Can you clear a code and have it go away?
I am assuming the mechanic (Audi guy) checked. I haven't looked at it myself having just picked up the car a couple hours ago. Is the battery light always--under normal conditions--associated with a fault code?

[lswing]

Not sure. Guessing they did something wrong with install or wiring, voltage is off for some reason.

[Dmb408]

Did they run the car dead because they didn't disconnect the on star back up battery (when they likely for safety reasons unhooked your battery to do the work).

[Dmb408]

Oh in addition to my above comment, i'd put it on the tender over night for a couple nights and then see if it sorts itself.

[UrS6]

Did they run the car dead because they didn't disconnect the on star back up battery (when they likely for safety reasons unhooked your battery to do the work).

Possibly. There are no codes that seem to pertain to the battery. What do I do to check the on star battery? The battery light in the cluster is fairly dim. Not fully lit.

[A4V8swap]

Test the output right off the alternator. Check your belt. Is it frayed or damaged? Good tension? Does it go away if you rev up the car? Does the light come on when you key on and do not start the car?

[UrS6]

Test the output right off the alternator. Check your belt. Is it frayed or damaged? Good tension? Does it go away if you rev up the car? Does the light come on when you key on and do not start the car?

The belt looks fine. The light goes on with the key in ACC position, off while cranking and then on faintly when running or driving at all speeds and idle. I'm getting 14.15v at the battery terminals at idle and 14.25 directly at the alternator. The battery reads 12.55v. I did notice something cracked at the alternator but it doesn't look like the VR but rather a plastic cover where the bolt for the main lead goes through. I pulled the small wire off and reseated it and did the same with the large/ main wire. Did a capacitive discharge. Started it back up and the light was on 2 seconds later. Just a reminder, it is on faintly and sort of pulses and flickers sometimes. I notice when I pull away from a stop it will flicker. It's always on though. Never goes out. It just varies in intensity and never is fully on.

[LaserSVT]

Most alternators in modern cars have 3 main wires. Large charge wire (which yours seems to work), an exciter wire that energizes the charge field and a wire that simply illuminates the battery light. If it is faint that means that wire is loose or grounding OR the regulator was installed improperly.

Now the 12.55 at the battery has me worried. Is that running or off? Because if its running then you need to check the battery terminals for good tight connections and you need to check the grounds. .5v loss is acceptable with a trunk battery, nearly 2v is not.

[UrS6]

Most alternators in modern cars have 3 main wires. Large charge wire (which yours seems to work), an exciter wire that energizes the charge field and a wire that simply illuminates the battery light. If it is faint that means that wire is loose or grounding OR the regulator was installed improperly.

Now the 12.55 at the battery has me worried. Is that running or off? Because if its running then you need to check the battery terminals for good tight connections and you need to check the grounds. .5v loss is acceptable with a trunk battery, nearly 2v is not.


12.55 is just the disconnected battery. I only see two wires. I'll have to see if there is a third. It's a cluster up in there. Hard to see

[LaserSVT]

Sorry as I have yet to tear into one of these. I do see that the regulator has two terminals for the plug. They may not both be used. If only one is used the exciter and voltage sense wire are one in the same. The dim battery light would indicate a presence of AC voltage which would indicate a faulty regulator. Put your DVM on AC and see how much AC voltage is there. If you have a good unit like a Fluke and see more than 1 volt you have issues. Should see maybe .5 volts. A scope is better to use in this case.
Cheaper DVMs are a waste of time on this test because they get a little freaked out.