I just noticed that the connector on my alternator is connected backwards. Everything works correctly and I am afraid to reverse it. I am not sure what would happen it I changed it to the correct position. Any help would be appreciated.
Ed

 

I would review the wiring diagram and make sure someone did not reverse the wires in the connector.

 

I believe normally Pin 1 connects to battery terminal and sense voltage and tells the alternator to increase or reduce the voltage. Pin 2 is connected to the ignition and will allow power to flow to the battery and other components with the ignition key on. Now, assuming you have them swapped, Pin 1 is now connected to the ignition and Pin 2 is now connected to the battery.

Maybe, since ignition is connected to Pin 1 and is off (0.0 volts), it is telling the alternator to not put out any power, my guess only....

I would make sure the wires aren't Bubba-up and then swap the connector.

Richard

 

Thank you for your thoughts. I have checked other alternator pictures of the same year and the wires in the connector is correct. I dont know how long this has be connected this way, but I am guessing a long time as the alternator has not been disconnected for as long a I can remember. The alternator was rebuilt about 20 years ago. What damage could occur if I put the connector on correctly?
Ed

 

Usually reversing the wiring causes a decent battery drain that will quickly discharge your battery when the car is parked. There have been a few cases of people finding alternators with the terminals reversed internally so they only worked correctly with the wires connected backwards to what is expected.

 

I would say it's correct, or it would not have made it 20 years.

 

Thanks, this is what I was thinking, but am not sure how to go about determining what to check inside to see if it is backwards. If this is true, that the connections inside are miss-wired, I would not have known to insert the terminal backwards. It just bothers me that the terminal is in backwards, and I dont know why. The battery that is in the car, is a restoration battery, that is 8 years old. I am not experiencing any drain issues.
Ed

 

pandora

 

Those terminals are part of the voltage regulator. It's impossible to install the voltage regulator backward (it will only physically fit one way) so the terminals are correct provided you have the correct voltage regulator for your application.
You are correct in your assessment that the plug, and thus the wires, are installed backward.
The brown wire is the "field" wire and connects to terminal 1
The black w/white tracer is the sensing wire and connects to terminal 2
You will find the terminal numbers cast into the rear housing just beneath the two wire plug.

You should use a volt meter just to check what's actually going on.
What voltage do you have for terminals 1 & 2 when the key is off VS when the key is on

 

The voltage regulator is a molded piece that is specifically designed to fit into that alternator case and it has the terminals directly coming out the side of it. So, you can't tell if the regulator is built with the terminals backwards by taking the alternator apart.

Was the connector ever replaced with a new pigtail? I've seen those with the wires put into the connector housing backwards before. Could be they got swapped and then whoever did it turned the connector instead of fixing it correctly.

Otherwise, if it works with no battery drain then it appears it's wired correctly regardless of it appearing to be wrong.

You can take the terminals out of the housing and swap them if you really want to turn the housing around.

 

Those terminals are part of the voltage regulator. It's impossible to install the voltage regulator backward (it will only physically fit one way) so the terminals are correct provided you have the correct voltage regulator for your application.
You are correct in your assessment that the plug, and thus the wires, are installed backward.
The brown wire is the "field" wire and connects to terminal 1
The black w/white tracer is the sensing wire and connects to terminal 2
You will find the terminal numbers cast into the rear housing just beneath the two wire plug.

You should use a volt meter just to check what's actually going on.
What voltage do you have for terminals 1 & 2 when the key is off VS when the key is onLast edited by Hammerhead Fred; Yesterday at 11:42 PM.


Thanks for the direction. I checked the voltage on the wires. The bk & white wire is hot with the ignition off and on, the brown wire is hot when the ignition is on.
Ed


The voltage regulator is a molded piece that is specifically designed to fit into that alternator case and it has the terminals directly coming out the side of it. So, you can't tell if the regulator is built with the terminals backwards by taking the alternator apart.

Was the connector ever replaced with a new pigtail? I've seen those with the wires put into the connector housing backwards before. Could be they got swapped and then whoever did it turned the connector instead of fixing it correctly.

Otherwise, if it works with no battery drain then it appears it's wired correctly regardless of it appearing to be wrong.

You can take the terminals out of the housing and swap them if you really want to turn the housing around.

I am sure the connector is wired correctly, as I am the original owner and have looked at other alternators to see how they are wired. I must have connected this wrong some years ago. Unless someone tells me I am going to damage something by putting the connector on the way is was suppose to be, i am going to turn it around and see what happens.
Thank you for all your help.
Ed

 

Hi Ed, I just checked my '71 and the connector is installed correctly. So if you reversed yours it would be the same as mine, brown to the right and black/white to the left, push tab on bottom, opposite as shown in your photo.

 

Thanks for checking
Ed

 

I suggest checking the voltages on the connector then or checking the shut-off battery draw. If you just swap it, it likely won't hurt anything but it might drain your battery rather quickly.

 

Does the battery light come on, then off after start up?

 

No battery light, amp meter.
Ed

 

There's no battery light on a 72.

 

https://www.corvetteforum.com/forums...-corvette.html

 

So are they plugged in the correct spades on the regulator?

 

According to all the information and testing, it looks as though everything is in the correct place except for the plug into the alternator. I am going to plug the connector in the right orientation in the alternator and see how it acts. I want to thank everyone that gave me the information to evaluate my dumb move, not paying attention to make sure that a plug gets installed properly.. I will let you know what happens, but to test it properly the car needs to be run somewhat, but winter in the NE does not give that opportunity.
Ed