Putting things together after dumping the engine and trans back in.

In the engine harness, the group that leads to the alt, oil pressure sender, temp sender and DVAC I have located a blue wire thats been cut with no GM connector etc. Just a loose blue wire.

Now I know that the oil press sender has a blue wire and I definitely have that one connected to the oil press sender so it isnt related to that.

I have all my other connections, the batt and alt plugin etc but have no idea what this blue wire is or was for.

Anyone help?

 

Heres a pic to assist.......

 

Is that a new harnes or old?

 

I believe it to be the original harness....

 

Just shooting from the hip here, but did that car originally have an internal or external voltage regulator? I think I see a black splice on the white wire to the alternator. (yes-no?) I think the 2 wires going to an external regulator alternator were blue and white. I'll check on my '70 this afternoon when I get up to the garage.

 

i don't know if this will help but my 72 cutlass s 350 has a blue & white wire in that plug going to alt . looks like the same gauge wire that your holding .BILL

 

Thx for the help fellas.

Yes it appears to me that the white wire was spliced into a brown or tan coloured wire.

I have no idea where this blue one went to or what connector might have been on it. I retaped the whole harness so I'd hate to rip it apart again!!!

My bad, I should have noticed it before I taped it up....

The car does have a voltage reg screwed to the firewall from what I can tell...

 

It may have a regulator screwed to the firewall, but it is not being used, as you have an internally regulated alternator.

- Eric

 

Do not know if this helps-70 350 Cutlass with external regulator that, like Eric said,is not being used

Ted

 

Ted, on the other hand, does have an externally regulated alternator.

I'm not sure what you mean when you say that your external regulator is not being used, Ted. Have you installed some sort of a replacement?

- Eric

 

I re-read my post-oops
I was trying to recognize what you had said in your answer,but it did not work.
My system has an external regulator, but since hot442 is internally regulated I did not know if my pic was any use to him-thanx for pointing that out Eric

Ted

 

Shooting from the hip again because I'm too lazy to look it up right now, but isn't the blue wire for the alternator light? And wasn't it about 73 when GM started using the internal regulator? And wasn't it 73 when GM switched from amp meters to volt meters? I'm thinking the volt meter change went with the regulator change.

 

As others have suggested, the two wires originally running to your old externally-regulated alternator were blue and white. I can't tell from the photo, but the red wire out of the connector must run to the threaded BATT post on the alternator. The white wire out of the connector must eventually be connected to the brown wire that goes to the ALT light.

 

Okay fellas so if I'm following correctly, my upgraded and obviously non stock alt is internally regulated, therefore this blue wire leading nowhere is just needed when one has an external regulator?

The white wire is leading to the brown wire yes. Looks like the prev owner spliced it in, maybe the original broke etc.... I'd also guess that since the alt has been replaced, the blue wire was snipped and left hanging.

So for now I guess I'll simply heat shrink it and tape it neatly aside.

Thanks again for all the advice and help all!

 

The wire plug in the alternator is different between an internal and external regulator. That's how you can spot the difference. Whoever did the conversion simply got a connector with a pigtail and spliced it into the harness to make the conversion and clipped the blue wire since it isn't needed.


The connecters on the internal look like this ( – – ) and an external looks like this ( | | )