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Dash light question

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Gundy

Gundy

Luke Skywalker
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While I was installing a aux 12v source in the BE I noticed
an unattached bulb holder hanging loose.
My Speedo and tach aren't stock BE so I'm assuming the holder
is for a stock unit.
I installed a bulb (screw in type) and it lights up.
Thing is it lights with switch off and goes out when I turn on the switch. Sparks fly if I touch ground with the holder.
Any thoughts as to what the bulb is for and why it works with switch off and not with switch on?
I've removed the bulb I installed and isolated the holder for now.
All gauges are lighted and I was thinking this might be the generator light which I currently don't have.

EDIT:

Nevermind. :jester:

It is the generator light according to the wiring diagram.
Bad news: my alt is a one wire deal. Guess I'll see if the gen/starter shop can change my alt to a two wire sometime
this summer when I have nothing better to do.
:wink:
 
That has got to be it Gundy. Even though most alternators claim to be single wire, they all have an idiot like connection. One that gives you a ground when the alternator is not charging and 12v+ or so when the alternator is charging. You got a hot on one side of the bulb when you turn the switch on and the other side has the ground through the alternator. When the alternator starts charging then you have 12v+ on both sides of the bulb and the light goes out. Now yours sounds like its not wired right,it sounds like it might have to do with something that was + ground.
 
This unit is a one wire. Just the one lug on the back of the alt.
I agree it's probably a ghost from the original positive ground.
The terminal end of this wire is hot at the alt end just nowhere to attach and prior owner just insulated/isolated the end.
Maybe when I get around to some "chores" on the Sprite I'll drop the alt off to my friend and he can make a conversion for me. I still haven't installed those wire hubs on the front and
Alan is working out a rear disc setup we might install.
And it still needs painting. Sigh....so much to do.
That is also why I love the BE. Hot Rod Tinker Toy!
 
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