3G alternator no charge light wiring

51504bat

51504bat

Well-known member
I'm installing a 3G alternator on the 302 I'm putting in my '54 Ranch Wagon. I wired it like the 2 attached diagrams show and it charges fine but I can't figure out the idiot light or no charge light as Ford refers to it as. My guess is that the light assembly isn't just a typical light socket with a hot and a ground. Can anyone shed some light on this? (no pun intended) Thanks.
 

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The wire going to the "I" terminal on the alternator is connected to one lead on the light,and the other lead on the light is connected to power when ign is "on". No other wires should be hooked to the "I" terminal if you're using a warning light. The light should be sized like a typical dash light,and have two wires coming from the socket (not grounded to the mounting point). The power to the "I" terminal travels through the bulb filament to energize the alternator.
 
cadillac512 said:
The wire going to the "I" terminal on the alternator is connected to one lead on the light,and the other lead on the light is connected to power when ign is "on". No other wires should be hooked to the "I" terminal if you're using a warning light. The light should be sized like a typical dash light,and have two wires coming from the socket (not grounded to the mounting point). The power to the "I" terminal travels through the bulb filament to energize the alternator.
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Kind of what I figured, I've got the wrong socket. Question is where to get the socket. So far Mr. Google has let me down.
 
KULTULZ said:
!!! THANK YOU !!!​

For not using the one wire GM ALT.
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Ford in a Ford, oops except for the Chevy distributor in my 8ba flathead. And the 1 wire GM alternator cause I had the mounting bracket. Didn't want to re invent the wheel to install a 3G on a flathead. The GM works just fine. No issues of not charging until revved. Mine charges at idle as soon as it starts.
 
51504bat said:
Ford in a Ford, oops except for the Chevy distributor in my 8ba flathead. And the 1 wire GM alternator cause I had the mounting bracket. Didn't want to re invent the wheel to install a 3G on a flathead. The GM works just fine. No issues of not charging until revved. Mine charges at idle as soon as it starts.
Click to expand...

So you have sinned ...
 
It needed a 2 wire single pole socket like one used in an oil pressure idiot light system. The key sends power through the light to the alternator which acts as a ground when it isn't charging so the light comes on. As soon as the engine starts and the alternator starts to charge the ground is broken for lack of a more technical term and the light goes off. Like a oil pressure light switch. Power to the light with the sender providing the ground. Once you get oil pressure the sender breaks the ground and the light goes off.


https://www.americanautowire.com/shop/single-contact-socket-with-ground-wire
 
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Yep, with 12v to both sides of the bulb it will not illuminate. That's the way most alternator charging system lights function.
 
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