I have searched all 6 pages in wiring section and didn't find a write up for this. The ford 3g alternator from 95 mustang gt has 3 wires and the miata harness has 2 not including the large wire that goes to the lug. How do the three wires integrate to miata harness? This is the last bit of wiring and I should be able to have a first start this week with my MS2 set up

 

"There are only two splices to make between the miata harness and the ford 3G alternator. 1. The original large gauge white miata alternator cable with the eyelet is simply attached to the (B ) stud at the back of the alternator. 2. The two splices required are the two smaller gauge miata alternator wires that need to be attached to the 3G voltage regulator plug. The small gauge white/black miata wire is attached to the ford green/red "I" wire and the smaller gauge white/green miata wire is attached to the ford yellow/white "A" wire. The center white wire on the ford voltage regulator plug is the "S" stator wire and gets plugged back into the rear of the alternator with a spade like stator plug."

 

awesome, thanks for the quick response!

 

I was super excited to see how easy this was, but when I tried, for some reason if I plug the white/green to the yellow white, it blows the main fuse.
So I tried just plugging the yellow white directly to the alt power post (like you said is an option and how the wiring diagram shows it) and it was fine, but the alternator doesn't seem to be charging the battery. Should I try and hook the green/white to the yelllw/white while it's on the alternator power post (b+)? Not sure why it's blowing the main fuse when the green/white and yellow white are hooked up.. any help would be greatly appreciated!!

 

Turns out, it wasn't the gr/wht connection that was causing the main fuse to blow (which was rather confusing to me), it was the 4ga wire I had bought that had too long of a metal piece, and was grounding out on the alternator case while being connected to the alternator post.

However, even after replacing my voltage regulator, and trying the gr/wh to yel/wh Im still not charging. I also just went yel/wh to the alternator pos, and still nothing.

Im hovering at 12v with the car on, so clearly somethings wrong. Not sure what it could be though... only thing I can think of is possibly a bad alternator all together... :9

Any thoughts would be greatly appreciated!!

 

The wiring given in this thread was not consistent with the wires on my sn95 alternator. I will look/post pics of my wiring when I get home today. Also, do you have the dash and rest of wiring in the car? Without the charging indicator on the instrument cluster the alternator will not charge.

 

The dash and wiring are all in so I think that should be good. I may grab an alternator from a junkyard today just to see if that's it. I'm pretty baffled :/

 

Ok so you mentioned the light for the charge indicator, and I figured I would double check. All other lights on my dash come on when key on engine off, but that one. Does the fact the lights not showing up mean the wiring is wrong to the indicator and therefore not getting a charge???

 

Here's a picture of my missing charge indicator light with KOEO. I'm guessing this isn't normal, and since that wire sends a signal to charge (from what I've read and understand) then this may be my issue.

 

I would bet so. Without the indicator alternator won't work. There are two plugs that go in the back of the cluster and one by passenger feet that carry all the wiring for this. Assuming those are all plugged in, you may just need to replace the bulb?

 

It was indeed the charge indicator wire! I jumped from the alternator to the wire at the gauge, and it works! Not sure why that wire is messed up.. something must be wrong with it somewhere along the way, but I just bipassed it and I'm charging 👍🏻Thanks all!

 

Have you stripped out some of the Miata engine bay wiring? If so, maybe it got snipped.

 

Well I did inherit someone else's project. I purchase a "finished" 5.0, but have since replaced the trans, motor, wiring, many welds, bracing, etc. it was a bit of a rats nest of wires. So I wouldn't be surprised. However I did use the wire at the alternator, and it was in the gauge cluster, so assumed it was complete all the way. You know what they say about assumptions...

 

I know this is kind of old, but did this get resolved? I am trying to wire up a Ford 6G alternator, but the wires on my 91 Miata are the thick white, black/green, and white/black.