Wow, thanks guys, this is some great information!!

The old resistors measure correctly so I've just kept them.  I guess
resistors last a while.  There's a capacitor back there that I did replace
though.  It read 2u2 which apparently means 2.2uf.  I replaced it with a
unit from radio shack (the same as this one:
http://www.ebay.com/itm/2-2uF-2-2mfd-50V-Non-Polar-Axial-Capacitors-2-2-uF-15-/380260188465)
It's slightly bigger than the old one; I think because its non-polar.

On Thu, Jun 7, 2012 at 7:10 PM, Dennis Haynes <d23haynes57@hotmail.com>wrote:

> The alternator warning light circuit does much more than simply make the
> light turn on. The circuit has two important functions. When the ignition
> is
> switch on the 12v goes through the resistors to allow enough current to
> "activate" the alternator". Some rotor current is needed to get the
> alternator going. Now when the alternator goes it will provide voltage back
> which will cancel out the current and causes the light to go off. Now here
> is the important part. When you turn the ignition off the alternator is
> still providing current. Without resistance or a blocking diode the back
> feed will keep the ignition energized and engine thus running. Things get a
> little more complicated with the campers as this circuit is also used to
> operate the fridge relay. A unique part of this is the use of the starter
> solenoid for the ground of the relay coil.  This disables the relay during
> cranking and if the alternator fails.
>
> Dennis
>
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
> pickle vanagon
> Sent: Thursday, June 07, 2012 4:50 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: more mysterious circuitry
>
> Mysterious to me at least... I'm sure to the Beierl's of the word it makes
> perfect sense!
>
> The alternator led circuit has me confused.  (This is shown, for example,
> on
> 97.74).
>
> It goes from 12 volt power supply, splits into two tracks.  The first track
> goes through a 60 ohm resistor, the second track goes through a 470 ohm
> resistor and then through the alternator led, and then they meet up again
> and go through a diode on their way to the alternator.
>
> (The 60ohm resistor is actually two 1watt 120ohm resistors in parallel).
>
> Why does this need to be like this?
>
> My curiosity stems from the fact that I have two 1 watt 100ohm resistors
> available, and I'm wondering if I can replace those 25yr old 120ohm
> resistors with them, or if I need to leave them be.  I'm also wondering
> what
> parameters I need to worry about from the standpoint of upgrading that
> LEDto
> something brighter.
>
>