Quote:

Don't use the red wire on the pigtail.



Although, if you want to get tricky, it can be used.

You can install a flashing LED indicator light in the dash (I put mine on the voltmeter) to indicate discharge. The ones from the auto parts store or Radio Shack have black bezels and the bulb is dark when unlit, so it's barely noticeable when not on.

Wiring is red wire off the alternator pigtail (in your particular case) to the negative lead of the LED. Positive lead of the LED goes to a switched source of 12V under the dash ("RUN" or "accessory"). LED is it's own diode, so current only flows when dash has power and alternator is not doing its job. Works well.
Got one for the oil pressure also (had dual sender, one terminal for gauge, one for switch to LED)