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In the attached scans of the 115c and 120c wiring diagrams there is a slight difference in the voltage regulator wiring. Wire # 23 appears to simply be a (n additional) ground wire running from the voltage regulator to the generator. My objective is to verify/understand the new wiring harness, having 4 wires at the voltage regulator noted as A B F and ground and at the generator as A F and ground is compatable for either an autolite or a delco regulator/generator. Hope my question makes sense as I am no wiring expert. Comments please, thanks in advance.

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If you had the extra wire included it would be usable for both.

If you look at the regulator diagrams, the Delco (115) from today and the other model Delco they used (posted on your other thread yesterday), they both have the regulator components connected to ground internally. Apparently Delco's use the mounting screws & bolts and body sheet metal for ground continuity & probably have a wider latitude for the inevitable voltage drop or poor connection.

The Autolite (120) brings all internals to the ground terminal and then straight to the generator frame & reference each other directly. The Autolite would work by connecting that terminal to a mounting screw and using sheet metal as the Delco. However, components may be more sensitive and calibrated differently so probably not have compensation for the voltage drop or resistance.

Later cars all ran a ground from the generator, some directly to the regulator area and others to a sheet metal bond on the fender. Some regulators (Delco from yesterday) have an extra frame terminal that can go to sheet metal or the ground wire even though they are internally grounded. It's an additional safety connection in case something comes loose.

By having the wire, your customers could choose to use it even if not required, or cut it off under the loom if there were no place to attach.

As noted by HH56 the Delco regulator is grounded through the mounting screws to the body sheet metal and does not have a terminal for a ground wire. Where it differs from the Auto Lite regulator is internally as there is a second armature winding in the voltage regulator section that is grounded at one end internally and gets power from the ignition switch via wire #18 to the IGN terminal. The hard wired ground would be redundant for the Delco system but the connection to the ignition switch is necessary for it to function properly.

I'm bad. Thanks BDeB for catching it. I casually noticed yesterday that Delco's had the wire, started to mention it then got fixated on grounds being the difference. Didn't go back to the ignition wire since other regulator had it-forgot both were Delco's. Totally skipped over it today.

HH56 - no insult intended in starting this thread specifically rather than tagging onto the other one, in fact, I meant to reference back to your prior reply, but got distracted by not figuring out how to load the pdf file. Apology hereby submitted.
The wires at the ignition switch, 13, 19, 18 look consistant/same to me?

Not to worry as long as things gets ironed out. BDeB can check my theories, but looks to me like the short section over to regulator area should have 5 wires in your new looms.

Ground 23 from generator may or may not be used and cut off & same for ign lead 18. As long as they're both present and explained to a new owner, would think anything could be covered. Only thing is 18 would be hot if connected at switch so would need to be well labeled as whether to use or not.