Recently, my "volts" light has been on (but like, half on, 25% on, barely on, and often off), but the system voltage seems normal (12.5v off, 14.5v engine running, accessories off), the battery is new-ish, and the gauge itself shows voltages in the normal range for the current duty cycle (off/running, AC on/off, etc). I did recently have the rally pod off to glue down the vinyl, but the connector pins are clean, and upon inspection, it looks like the logic switch that controls the warning light isn't in the pod anyway, and the light just connects directly to the two rightmost pins when looking at the back of the gauge pod's PCB.

Where does the warning light's logic happen? Is this a sign of some problem unrelated to out-of-range system voltage? Is there some ground that needs cleaning, that I haven't already?

The CHARGE lamp is connected to the GAGE fuse on one end, and the small plug on the ALTERNATOR (pin L).

The CHARGE lamp will only illuminate when there is a low voltage situation across the light.

At KEY ON the GAGE fuse has power, but pin L on the ALTERNATOR acts as a ground. The CHARGE light is illuminated.

When the ALTERNATOR begins to produce voltage, the CHARGE lamp goes out because pin L now has an electrical charge.

The CHARGE light is part of a voltage balanced circuit - when the circuit becomes unbalanced, the light will glow to varying degrees.

You might want to have your alternator tested......

turn key On, do not start. Should have a light in the dash or pod should be On.
If not then bulb, wiring or the Alt has problems.

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(Jurassic Park)

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Volts light is on with car off. I guess the intermittency of the light being on with the engine running is what threw me for a loop, as well as the normal voltage throughout the run cycle. I'll bring it somewhere to have it properly tested.

I had a similar issue. Turns out the tension bolt had backed off, and it wasn't charging well.

Got Dodgerunner's tensioner bracket, installed a tensioner, and fixed that issue.