GM one wire Alternator

Akamphi

Member
I picked up a marine version of the GM one wire alternator. I spoke to the supplyer and now realize it wont work with my blue check engine light wire. Anyone know if there is a way to run that light with these alternators? Will my dash light on or off without it?
 

jfriese

Active Member
Craig,

Why reinvent the wheel? Get the Lucas alternator and mount that came on your 1500 engine on later Spitfires. It mounts without problems, works the dash light correctly and even has the same terminals that the generator used so you don't have to change anything. Disconnecting the old regulator box is easy and the whole thing works fine.

John Friese
67 White
67 Red
 

Midwest Amphicar

Worlds Largest Amphicar Destination
Raise your hand if your car went dead because of a tiny bulb,or socket corrosion or loose wire. The reason for 1 wire alternator is dependability. Plus when parts go bad, no one stocks a Lucas Alternator. So after dragging your Amphicar down to ........... You know what will happen. The GM alternator has a delightful hum whilst it works,so no need for a dim bulb. Plus Tony Oratke stocks very nice original looking brackets. Later Dave the Wave
 

jfriese

Active Member
Gee Dave, I've run these in 2 cars for 9 years and never had a problem but it's always a good idea to have good wiring and clean connections at light sockets. Rebuilt alternators are available, though not usually stocked, at a local (I think national) auto parts store. They are rebuilt by some national company and I can get you the part number if you'd like. They are a bit smaller than the Delco models but still put out about 40 amps and look more correct. Oh, and they make the typical alternator whine just to let you know they're working.

John Friese
67 White
67 Red
 

Tedredamphi

Platinum Subscriber
Craig,
I wired up the GM single wire marine alternator on my Amphicar a couple of years ago and made the "blue discharge light" operational. Attached is a quick pic of the alternator rewire as you have to open up that rubber plug on top and run one connector to the brown "field" input and the other over to the "big" wire.
I'm on the way out the door for a week's vacation, so I don't have time to dig out the actual schematic until I get back. I think I found the wiring schematic either on an old Amphicar Forum link or a Google search.
The alternator and "blue light" both function perfectly.
TedALT.jpg
 

Tedredamphi

Platinum Subscriber
"quick and dirty" explanation of how to wire up the alternator and blue discharge light from oldengines.org . There are probably more sources - just do a google search.
Ted
The 10SI has three terminals (including those with a 1 wire regulator).
  • The large "BATT" terminal which gets connected to your battery positive. (Or Terminal Post if your vehicle is so equipped).
And a dual terminal connector. (Repair pig-tails for this connector available at any autoparts store. Or, salvage with alternator if pulling the alternator from a vehicle).
  • The #1 Terminal. (Marked with a "1" on the case)
    • This terminal is used to connect to the dash warning light.
      • For the warning light, a lamp is wired in series with a switched voltage source. During normal operation the lamp stays off. If the regulator is damaged, the #1 terminal provides ground, and the warning lamp will light. Usually.
    • This terminal is also active on 1 wire regulator equipped 10SI alternators.
  • The #2 Terminal. (Marked with a "2" on the case)
    • This terminal is used to excite the 10SI into operation. (3-wire 10SI)
    • It is connected to the battery positive.
      • For simplicity you can connect the #2 connector pigtail directly to the "batt" terminal on the alternator.
    • The terminal is present on 1 wire regulators. Used only for those that require the stock connector to fit snugly.
 

Akamphi

Member
Ted , I think I have that same alternator. Did yours come with a plug in that top port where you have two wires going in? I havent tried to pull teh plug on mine but if I do does it have a connector under it that I would run the brow and black wires to?
 

Tedredamphi

Platinum Subscriber
Craig,
I wrote this up over two years ago and totally forgot about it. If you click on my alternator picture it should enlarge and show you how it is wired. My marine alternator came with a black plug over the terminals which I removed. I was able to get the pigtail from my local parts store. The black wire just runs over to the batt terminal of your alternator and the brown one goes to the brown wire from your "blue" battery discharge light in gauge.
My alternator has been working fine since installed and the only time I ever see the blue light is prior to start with ignition on.
Later,
Ted
 
No wheel to reinvent and like Dave says when it goes bad you can get at ANY parts store or junkyard! I changed my blue dash light to High Beam and alternator to red like it should be....apparently at the Amphicar assembly plant the floor didn't get the memo sent down from the engineers regarding this mistake?
 

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