blue alternator wire - battery light - no voltage

[tberk@mindspring.com (T Berk)]

Vince Royer wrote:
> 
> So does the blue wire go from the alt to the insrument panel or does it go
> to the battery?  does the alternator send 12v down the blue wire, or does it
> need to see 12 volts from the blue wire to work?
> 
> What if my blue wire is hanging unused because I thought it was only for the
> alternator light?  (Thus I haven't hooked it up to anything yet)
> 
> Vince



The Blue Exciter Wire runs into the Back of the Alt, from a  'You Ain't
Getting a Charge" light in the dash which in turn gets it's 12v from
Switched Terminal 15 power.

Now, there is a special doohiky (I hope every one can keep up with the
technical terms) that will only light the warning light _if_ the Alt
isn't putting out 12v (or more) of it's own, 'backwash' so to speak
keeps the light out. 

This same Term 15 (Switched Power, as in Only ON when the Ign key is in
the ON position), serves the Instrument Cluster & other warning lights
in the same dash area. Terminal 30 would be that 'Straight to the
Battery' power.

If the Alt turns but the Blue Wire doesn't provide 12v to the windings
inside, the initial electrical field (oops, I meant magnetic field)
can't be created, so the mechanical motion provided won't cut through
the magnetic field creating electricity. All you get is a spinning Alt
and a dead battery.

This whole thing explains why folks who have removed the dash but need
to drive end up running off the battery and don't know why. The Alt
Warning light needs to be in the circuit. (Well, it's not _neeeeded_ but
it is built in for a reason).


There, a whole bunch of woids to splain the hole ting.

TBerk
How do I know  this? I read my BENTLEY! Don't got one? Get One! 
[Use of paraphrased excerpt from Toy Story used without permission].