Alternator Change

[Floyd57]

Hello to everyone, I am new here and felt it might be one of the forums where most would help a person out instead of running them out. My dilemma is this:
I replaced a 302 Ford engine into my 1997 Ford F150 4x4 Supercab. It had a 4.6. Now, I got an alternator wiring problem. I don't know the charging circuit and I need one. I want to install a 3g alternator or even a 2g if possible. I just don't know the color code for the circuitry to get my needle gauge to work. Any help like always in times of real need would be appreciated. I likewise will offer my help if you need some but if you know this you know more than me. floyd

[Floyd57]

Newbie and need some information

Hello, My name is Floyd and from Tennessee. I am hopeful that I can share some information with others that need it. Like wise, i also would like to have some help with my wiring.

[Grand Marquis GT]

to GMN!

Sounds like quite the project. Pushrod power! And i'm glad you are able to post

[79lincolnlover]

Welcome!!

[85crownHPP]

Forget the 2g... what does the plug for the original alternator look like? It might plug in, then all you need to figure out is your charge wire.
If its not plug-in, hopefully wire colors will be similar to the 3G wiring.

[86VickyLX]

Pics would be a great help. What type of alternator did the truck have before? It might have already had the 3G. So if that's the case, you would need to find the 3G model that worked on trucks. Green with red stripe wire is the wire that completes charge circuit, orange wire with blue stripe is self excite wire, and white with black stripe wire is the stator wire which would plug into the single prong plug on the side of the alternator. Orange wire would go wherever the charge wire would go. There should also be a fuse at the end of the charge wire, or fusible links so the circuit is protected.

[85crownHPP]

No need to self excite the 3G... once you find the old alternators wiring, just hook up the yellow wire from the 3G into the cars key-on excite wire.
Hopefully the indicator wire will work with your battery gauge once you hook that up too.
Lots of threads here with good directions on how to do it right.

[gadget73]

Its not the yellow wire. Thats the battery sense wire, and should be tied to battery voltage (or the output stud also works fine). The green/red is the exciter wire and needs to go to key-on hot. Its also the idiot light circuit wire. White/black is the stator output wire, and jumps from the regulator to a small plug on the side of the alternator.

[1987cp]

[85crownHPP]

interesting... I didn't know the green was both. I wonder why they didn't take care of the 'sense' circuit internally...

[gadget73]

Don't know honestly, probably just a holdover thing from the old style external regulators. I guess it could also be argued that the battery voltage will be slightly lower than what you see at the alternator due to loss in the cables, but I can't see it being enough to matter if the charge cable is heavy enough.