Hi Theo:
Well, I think I'm getting there (one tiny step at a time):
The first problem is that I'm too literal--I thought a one-wire
alternator only has provisions for one wire. I now know that's not
entirely true, but I was going nuts trying to understand where this
'second wire' came from, since all I could see was the big battery post
on the back of the alternator.
Your letter and Frank Marrone's helped get me on the right track
(embarassed hanging of head and digging of toe into ground:-)
Based on Frank's comments, I called the vendor and asked if I had been
sold the 'self-exciting' alternator, which the vendor confirmed. I then
asked what was involved in converting to the additional terminals both
you and Frank had mentioned. He said they were already there, under a
rubber plug on the side of the alternator (as Frank had already said).
After two trips to the car to look I finally found the plug and the two
spade connectors it conceals. AHA! I says, says I. More connectors
makes sense of what everyone has been trying to tell me.
Evidently the 'one-wire' has more than a single wire hookup point,
though not all the hookups may be active at this time.
The vendor tells me the idiot light circuit might still be connected, he
wasn't sure. If it isn't, he can reconnect it for a nominal sum.
Anyway, Steve Laifman's earlier comments about the Toyota alternator now
make more sense, but my Toyota manual shows an L,B,S & IG on the
alternator and when I checked through the e-mails on this issue the only
other info I saw was from Curtis Fisher whose GM unit is using a PLFS
connector where the 'L' hooks to the idiot light. I wasn't sure how the
letters translated to my alternator which brings me to the next item
(and thanks for your all's patience on this):
There's two spade connectors--Labelled #1 (R) and #2 (F). Side question:
does the 'R' stand for 'Rectifier' and the 'F' for 'Field'?
Since my vendor is now closed for the weekend, my question is:
Which connector (R or F) goes to the idiot light?
Again, my thanks for all your patience.
Regards
David
Theo Smit wrote:
> I'll take a swing at it.
>
> First off: Read Larry's post carefully: One wire to the battery/starter
>solenoid,
> and another wire to the light. The one-wire alternator has TWO wires. My
>Toyota
> alternator has three: the output wire (big bolt-on post) and two spade-lug
> connections, one for the ignition and the other for the light. The "one-wire"
> alternator combines the function of the last two connections, and Steve L's
> description of its operation is pretty much correct: When the ignition is on
>but
> the engine isn't running, the alternator doesn't put out any current, and its
> internal regulator pulls some current from the 'light' connection to turn it
>on.
> When the engine is running the alt output is above some threshold, and the
> internal regulator turns off its current switch for the 'light' output. When
>the
> ignition is off the voltage at the light is zero, and the alternator's
>regulator
> takes that as a cue to do nothing. If your charge light is on when the
>ignition
> is off then either the light is wired to the wrong side of the switch, or
>there
> is some internal fault with the alternator that is allowing the current flow
>in
> the wrong direction (some older cars had the diode Steve and Tim Ronak
>referred
> to on the instrument panel circuitry but this newfangled alternator shouldn't
> need it).
>
> So we should have
>
> 12V ---> ignition switch---> (run position) -->light--->alternator 'red' wire
>-->
> alternator.
>
> Clear as mud? Let me know - I can try and draw you a schematic and email it.
>
> Theo
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