led battery warning light ~ for kill switch ~ not working yet

[j12piprius]

I'm hooking up an led light at eye level at the edge of the hood that mimics the battery warning light, so I won't have to look at the dash. However, ideas are needed, as the light is not working yet.

> led light with wires, tested at battery to be good;
> spliced into alternator warning light wire at 10p connector by power steering fluid;
> verified this is the right wire (blue/white), as it doesn't work on the dash after cut;

> led light piggybacked from b/w wire to ground ~ led light doesn't work;
> current from b/w wire, through led only, back through b/w wire ~ led doesn't work;
> regular battery light works as usual when spliced together ~ but not the led light.

The led light does have a resistor. Could that be the reason it's not working?

Or is the dash light getting power from somewhere else, other than the blue/white wire?

[jakobnev]

At the risk of insulting you: Is it turned the right way?

[j12piprius]

Originally Posted by jakobnev

At the risk of insulting you: Is it turned the right way?

Yes, good question. The light only works one way at the battery, i.e. red wire to positive, black wire to negative, but doesn't work either way at the blue/white warning wire.

[Occasionally6]

Maybe start with the basics; do you have a voltage (wrt to your ground) at the blu/wht wire? You may be on the "wrong" side of the lamp.

Alternator warning lights can be "different" in their operation. While some are a simple - sometimes relay controlled - switch, some are part of the regulator control circuit.

They can be switched on by removing a voltage - initially applied to either side of the lamp - rather than lit by simple switching to ground. What happens if you connect the LED light across the wires or PCB traces directly at the alternator lamp i.e. in parallel with the lamp? You may have to access the instrument cluster PCB for this.

[j12piprius]

Originally Posted by Occasionally6

Alternator warning lights can be "different" in their operation. While some are a simple - sometimes relay controlled - switch, some are part of the regulator control circuit.

I finally got the led to go on by connecting from blue/white wire, through led wires, back through the other blue/white wire, in series. This didn't turn on the led before but now it does; however now the warning light doesn't work! This would be okay with me, BUT might be upsetting the balance.

Better would be to have both lights go on, in parallel, in case the led fails, but the led doesn't go on that way.

Update: I drove the car around my 2.7 mile loop, the alternator was charging and all appeared to be well. However, the led was harder to see than the battery light, so I've reconnected the battery light back to the way that it was.