Alternator Connections
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Joined: Oct 2013
Posts: 76
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From: Visalia CA
Alternator Connections
I have a 3-wire (+ground) alternator w/built-in regulator in my '74. Presume that's not what came with the car.
Re the connections - everything NON-Corvette I read says:
1. the main batt. connection on the alternator is constant 12v
2. #1 flat connector is switched 12 volt w/ignition
3. #2 connector is a jumper to the main batt. connection, so it is also constant 12v.
I actually hooked it up this way and everything seems to work fine.
However my Vette wiring diagram plus evidence in the car indicates that there are two separate wires running from the main batt. connection on alternator and the #1 flat connector - but BOTH go straight to the junction box and are both constant 12v.
Can that be right? If so, you might as well just run one wire to the alternator and jump the other two connections! Also, with power to the alternator constant, isn't there a probability that you can discharge the battery with the car off?
Thanks in advance for your input in helping me understand this.
Re the connections - everything NON-Corvette I read says:
1. the main batt. connection on the alternator is constant 12v
2. #1 flat connector is switched 12 volt w/ignition
3. #2 connector is a jumper to the main batt. connection, so it is also constant 12v.
I actually hooked it up this way and everything seems to work fine.
However my Vette wiring diagram plus evidence in the car indicates that there are two separate wires running from the main batt. connection on alternator and the #1 flat connector - but BOTH go straight to the junction box and are both constant 12v.
Can that be right? If so, you might as well just run one wire to the alternator and jump the other two connections! Also, with power to the alternator constant, isn't there a probability that you can discharge the battery with the car off?
Thanks in advance for your input in helping me understand this.
Le Mans Master
Joined: Jan 2000
Posts: 8,918
Likes: 27
From: New Hill NC
I have a 3-wire (+ground) alternator w/built-in regulator in my '74. Presume that's not what came with the car.
Re the connections - everything NON-Corvette I read says:
1. the main batt. connection on the alternator is constant 12v
2. #1 flat connector is switched 12 volt w/ignition
3. #2 connector is a jumper to the main batt. connection, so it is also constant 12v.
I actually hooked it up this way and everything seems to work fine.
However my Vette wiring diagram plus evidence in the car indicates that there are two separate wires running from the main batt. connection on alternator and the #1 flat connector - but BOTH go straight to the junction box and are both constant 12v.
Can that be right? If so, you might as well just run one wire to the alternator and jump the other two connections! Also, with power to the alternator constant, isn't there a probability that you can discharge the battery with the car off?
Thanks in advance for your input in helping me understand this.
Re the connections - everything NON-Corvette I read says:
1. the main batt. connection on the alternator is constant 12v
2. #1 flat connector is switched 12 volt w/ignition
3. #2 connector is a jumper to the main batt. connection, so it is also constant 12v.
I actually hooked it up this way and everything seems to work fine.
However my Vette wiring diagram plus evidence in the car indicates that there are two separate wires running from the main batt. connection on alternator and the #1 flat connector - but BOTH go straight to the junction box and are both constant 12v.
Can that be right? If so, you might as well just run one wire to the alternator and jump the other two connections! Also, with power to the alternator constant, isn't there a probability that you can discharge the battery with the car off?
Thanks in advance for your input in helping me understand this.
That should be the correct type alternator.
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Joined: Oct 2013
Posts: 76
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From: Visalia CA
Pix are my actual alternator connections, GM generic diagram, and my vette wiring diagram. FYI, the white wire coming off the alternator (spliced to red) connects to constant 12v through a fusible link. Needless to say, I WILL be cleaning up the wiring once I determine how I will connect it (remember this car was previous owned by a butcher!!)
Last edited by wayneyada; Jul 26, 2014 at 09:12 PM. Reason: more specific detail
Race Director
Joined: Apr 2007
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From: South Western Ontario
The #1 terminal must be switched or the alternator will drain the battery.
The # terminal is the voltage sensing wire and the best place to connect it would be a junction block where other loads connect or the solenoid where the battery cable connects. It will work connected to the stud but there can be a bit of extra voltage drop in the wiring it won't be able to compensate for.
The # terminal is the voltage sensing wire and the best place to connect it would be a junction block where other loads connect or the solenoid where the battery cable connects. It will work connected to the stud but there can be a bit of extra voltage drop in the wiring it won't be able to compensate for.
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