I recently found three good sources for SAE wiring harness two different places that will make custom harness and matching firewall connections. It's a great option for those that want to upgrade to a ATO fuse pane and are looking for a clean way to add a 8 gauge power feed to the Fuse Block. Or for needing a way to route a power wire to the trunk.

Just to add my two cents worth. Yeah 3G done.

Tubo

I am eliminating the dash light bulb to be replaced with a volt meter. On my 66, the exciter wire goes right to the alternator wiring and works fine.
Lots of rewiring will be done on this 65 convertible.

Mach1Driver wrote:

BobE wrote:

Mach1Driver wrote:

I recommend a 3G. Converting to a 3G can be a problem for some of us, particularly 67/68 cars with an alternator warning light, because apparently there are no wire diagrams for a 67/68 tach car. Does anyone have access to such a wire diagram? I posed this question of two other forums with no luck. I even found an article in Mustang Monthly also claimed the same problem- no diagrams for 67/68 cars with alternator warning lights (tach cars).

I Googled "alternator warning light wiring diagram for 1967 ford mustang", and found this hand made sketch, hope it helps.
https://www.hotrodders.com/threads/alternator-warning-light-for-67-mustang.181720/
This wiring sketch is typical of any warning light circuit.
 

Thanks, I know how it works, but I have been looking for a published wire diagram that shows all the plugs, where the splices are, with the wire numbers and colors. There are schematics in the charging section of the shop manuals but they don't get updated every year and a schematic is not a wire diagram. A schematic does not show plugs and the colors if shown are often out of date. Thanks for the effort. 

What car are you dealing with? I saw one reference to a 67/68 tach car.
 
I have a 67 Tach car with a Painless wiring harness. I had to make several changes to it since Painless doesn’t offer a factory tach option or at least they didn’t when I bought it years ago, about 2012. I made use of the Jim Osborne wiring diagrams for a 67 to help me along. This is supposed to be what Ford used during car assembly showing the routing and connectors. The connector location can be derived from the drawings to. Surprisingly, the Painless harness followed the Ford colors and numbers from this manual. The sketch is what I put together when I was figuring it out. Apparently, I didn’t add enough detail cause I can’t remember why I did things, but then again…… I made this so I wouldn’t have to remember!!!
 
From memory, the Painless harness came set up for the voltage regulator. The green with red stripe at the regulator was pulled back into the interior of the car to have enough wire length to get in and out of the cluster harness. The other wire at the regulator that went toward the battery was tied to the green w res stripe and extended to get to the alternator, I think. I added the diode at the light and have never had an issue with wiring.


 
Started out with the typical single V groove pulley that I couldn’t get tight enough. Moved to the Hi-Po pulley with a shim from a license plate to keep it from rubbing. I didn’t have a full nut on the threads either. Took it to the machine shop to have the material removed to keep it from rubbing without a shim and allow for full threads on the nut itself. No issues with alignment either. 




 
Depending on the year model car you are working on, this may be as close as you get to having all the info you want without diving into your car and tracing out the wiring.
 
I’ll give a plug to the Jim Osborne manuals cause I bought all that were offered for the car. I made life easier as I bolted it back together after being in some stage of disassemble for the better part of 20 years.