Need a help on my 95 Previa LE S/C AWD, battery warning light dimly stays on.

[isachan]

I have a question about battery warning light dimly stays on while driving.

I recently replaced the dash bulbs to LEDs and several times I moved the gauge unit to test and try again in the process.

So the battery warning lights up brightly at the ignition key position, but turns dim and stays on while driving.
It turns off at the key off position. I read the voltage on my Bluetooth scanner (Torque Pro) and read 14.5V at engine-on, 12.5V at engine-off.
Should I replace the alternator to a Toyota genuine part (Denso) ? The battery is made in 2013.
Also the airbag warning light dimly stays on both at engine-off and engine-on. Should I do the reset procedure to see it goes away ?

Thanks in advance,

Isao

[tbkilb01]

I'd start checking voltage drops on alternator and battery connections/wires. Loose connections and corrosion will effect charging...before condemning alternator/battery. The light is trying to tell you something is wrong. Wires and connections need to be perfect! Loose belt can also affect things too

[originalkwyjibo]

This is basic troubleshooting. If you recently worked on something and now you have a new problem, there is a high probability it's related to the recent work. The light is trying to tell something. It's trying to tell you it shouldn't be an led. I recently did this on a 1992 Saturn and discovered several of the circuits use the resistance of an incandescent filament as an integral part of the circuit. I had charge lights, upshift lights, check engine lights, among others doing weird things. Try swapping a standard bulb back in and I bet your light goes away.

[isachan]

Update:

So the dealer replaced the battery and corroded battery terminals and cables. About $350. Ouch.
Still the battery light stays on while driving...
But this time, Toyota dealer mechanic states that the diode inside of alternator is failing.

I gave a summary of what I found and people's suggestions on this forum and the mechanic looked in each item on the list.
He cleaned out battery terminals, cables, fusible links...

Thanks people, but I just can't afford $600 for a new alternator job at the moment.
After a several months down a road...

Isao

[originalkwyjibo]

Have you tried changing the bulb? It's a lot cheaper than an alternator.

[isachan]

So afterall, the alternator was the cause of the culprit. With a new unit, no more battery warning light while driving.
Still rattles on drivetrain under torque... Universal joints now ???

Isao