No Alt. light after start up but battery not topping off .. Options

[Literati914]

My battery was bought last month.. Alternator light comes on with the key on, but goes out at start up. Battery keeps running low and eventually won't start the car. Does this point to anything usual - VR maybe?

[Literati914]

update - the bulb is not blown. I can get it to light up with the ground provided by a test light.

You're aware that it's almost impossible to get the alternator to "excite" without a properly working GEN bulb?..

Yes of course, I posted about the light as a new issue once the belt was tightened. The point being, that now my Alt light is not coming on with the key - when it was before.

Idiotic admission: removing the alt plug at the relay board in order to check the voltages of the wires there, like @Spoke suggested ^^ and forgetting you've done so, will cause the Alt light on the dash to no longer illuminate. I plugged it back in and the light on the dash works fine again. Sorry for side tracking everyone.

About those wires... with the engine running, the red wire is showing a (guessed) average of about 1.3V .. the brown and the green are both showing .002V . So, that's a bad alternator, no?

[Spoke]

removing the alt plug at the relay board in order to check the voltages of the wires there, like @Spoke suggested ^^ and forgetting you've done so, will cause the Alt light on the dash to no longer illuminate. I plugged it back in and the light on the dash works fine again. Sorry for side tracking everyone.

About those wires... with the engine running, the red wire is showing a (guessed) average of about 1.3V .. the brown and the green are both showing .002V . So, that's a bad alternator, no?

If you unplugged the alternator please plug it back in to test. The test I suggested is done with the plug connected as normal.