alternator field bypass test

[prg machine]

I am trying to diagnose a problem with my alternator charging. How do you bypass field to the hot side of alternator at the 2 post connnector that plugs into the back of the alternator. And wich wire? Mine has a white wire on the top looking down from the hood and a blue at the bottom. I want to test the alternator since I can't find a problem in the wiring or the regulator which is new solid state a year ago. I believe the process puts the alernator into full charge and if not the alernator is the problem?
Any help appreciated.

[VetteVet]

Originally Posted by prg machine

I am trying to diagnose a problem with my alternator charging. How do you bypass field to the hot side of alternator at the 2 post connector that plugs into the back of the alternator. And which wire? Mine has a white wire on the top looking down from the hood and a blue at the bottom. I want to test the alternator since I can't find a problem in the wiring or the regulator which is new solid state a year ago. I believe the process puts the alternator into full charge and if not the alternator is the problem?
Any help appreciated.

Do you have this alternator?






If so you can jump between the large red wire on the alternator to the "F" terminal on the alternator which should be the white wire. If you have a voltmeter you can check for full output from the alternator large post and the alternator housing. Make sure that the small blue wire that goes into the plug has 12 volts or the alternator field will not energize. Also make sure that the regulator is grounded well to the radiator support and to the alternator and the alternator is grounded to the engine block.

Before you do anything, check for 12 volts on the regulator plug brown wire,with the key switch on and 12 volts on the red wire at the same plug with the key on or off. You know that you can take the alternator to Autozone and they will test it for free. If you decide to get a new alternator then get a newer 12 SI model and we will show you how to wire it.

[prg machine]

Thanks.
I ended up replacing the alternator. It sitll wouldn't charge. I spent hours replacing wire and checking connections. I believe it was the red wire terminal at regulator that was the problem. I am replacing that connector end ASAP> the charging circuit is working now after I carefully plugged in the regulator plug and the red wire clipped to the terminal.( it pulls out the back of the plug. Could have been the problem all along. Anyway I am keeping the original alternator in the tool box since I think it still works.
Thanks for the help