A wiring challenge for Tim or Mike, ..or others if you understand this kind of stuff. Options

[ThePaintedMan]

I've been on a mission to add a second set of brighter, more visible idiot lights since this car is mainly a track car. I bought a set of 2 cheapo 24-led green/red boat lights from Ebay (seen here). I wired the green in line with the existing oil pressure light and it works perfect - very bright and obvious on startup until it shuts off with adequate pressure.

However, I'm still stumped as to how the alternator idiot light is wired and if the same thing can be done with the red one. Someone posted an excellent thread awhile back explaining how alt light is wired to come when the circuit is no longer charging. But I can't figure out how to wire this red light up to work with it in the same way that my oil pressure light works. Obviously when I wire the led light in parallel with the existing alt light, it doesn't work the same way, ostensibly to the added resistance? Wondering if it's even possible to add a second light.

Sorry if this is confusing. I'll take some pics tonight to try and illustrate my point, but as always, thanks for your help in the meantime.

[stugray]

One simple way you could do it:

Hook up the proper resistors to precharge the Alt field winding.
Then put in TWO idiot light LEDs,one pointing in each direction.

The stock alt light illuminates when there is an imbalance between the two sides.
If the dash voltage is higher than the Alt voltage, current flows TO the alt illuminating the light
If the dash voltage is lower than the Alt voltage, current flows FROM the alt illuminating the light.

If you put a LED pointing each direction, ONE of them will illuminate for either condition.
Just make sure the LEDs are predesigned to be excited by 12V (the will have current limit built in)

Whether, or not, you can excite the ALt windings with the an LED is a different subject.