Alternator on 429 (1966)?

[blink182house]

So I finally got my car running/driving, and someone previous replaced the generator with a newer style alternator... driving to work today I broke down, car just died battery dead as a doorknob! Anyone have a diagram or simple description of wiring in the alternator on a '66? Should be relatively simple, I want to go check over how it was done and fix whatever the issue is, but I'm at work and no time to mess with it til it gets dark. Any help is greatly appreciated, thanks!

[blink182house]

Alternator Post has wire directly to positive terminal on battery.

Alternator Post has jump wire to alternator plug.

Alternator Plug goes to BROWN wire from voltage regulator plug.

[pdxmose]

Brown wire is GEN light.  Must have resistance in it to work correctly.  Was the Gen light working with key on prior to start?

The wires all sound correct for a conversion.  I'd start with making sure the GEN light is on and/or check the voltage on that brown wire when running and not running.  Obviously you'll need a charged battery to start with.

               ...mose

[blink182house]

The GEN light is on all the time when the car is running.

I went back with a lunch break and checked and it all seems proper, my battery wasnt too drained either with meter on it and i stuck another battery in real quick to check it. Wiggled some wires around and it started right up. I think I need to spend a day replacing grounds and redoing connections, old age has gotten to it I think! Hopefully that's it!

[pdxmose]

Is the GEN light on when not running as well?  Something's not quite right with the ALT hook up.  Can you figure out what ATL you have and what terminals the two wires are connected to?

               ...mose

[EZ]

Scott,
There is a guy on Ebay selling a laminated copy of the complete wiring harness for a '66 Cadillac.  It's only about $12.
I recommend you buy one.  I have one hanging on my garage wall.  It's in color and laminated so you can wipe the grease right off!!   

[blink182house]

Thanks guys, got back home and parked her. I'll be gone until monday, but when I return I'll snap a picture so you guys can see! Also, i think a big culprit of my issues is my battery is direct ground to chassis, there is no chassis/engine ground going on! Need to go through and cleanup a lot of the grounds, someone had the car undercoated very thick all over and I think that's creating issues.

[STDog]

Something's not quite right with the ALT hook up.  Can you figure out what ATL you have and what terminals the two wires are connected to?

Agree. I'm guessing the wires on the alternator are reversed.

I'm betting on a 10SI or 12SI alternator, and the connections should resemble this.


Note the wire in the plug farthest form the post (#2) goes to the post.
The other wire (#1) goes to the GEN light.

The pin numbers are stamped on the rear of the alternator, below the pins

[pdxmose]

... there is no chassis/engine ground going on! Need to go through and cleanup a lot of the grounds ...

Main starter ground strap should be between the outer starter bolt and the frame.  See this post for details:

http://www.modifiedcadillac.org/forum/index.php/topic,6879.0.html

             ...mose

[blink182house]

Thanks guys! Tonight I stayed up til 4am working on the car after work; changed the alternator with a new 'chrome' cheapy i had in the attic. Also added plenty of grounds that were missing, including the ground strap on the starter, thanks for the link above! Also added a ground from the starter casing to the head, not sure if that is originally how it went but figured a ground is better than none. I think I'm good! Charging, my lights and etc are working MUCH better, and car is running like a champ!

[3onthetree]

Scott,
There is a guy on Ebay selling a laminated copy of the complete wiring harness for a '66 Cadillac.  It's only about $12.
I recommend you buy one.  I have one hanging on my garage wall.  It's in color and laminated so you can wipe the grease right off!!   

  Me too brother, I have the 65 right in the top of the toolbox...I bet it was from the same guy on Ebay.  Invaluable.