Wiring Harness - Distributor - Alternator (1 Viewer)

Sep 16, 2012
North of Tulsa
My ’77 lead a very rough life before I purchased it. I knew going-in that it had lots of problems but after (8) years of ownership and very slow refurbishment I’m still discovering issues. (I'm not complaining.....I love working on it. It's therapy)

The most recent issue involves the wiring harness. From what I can tell (from searching this site) the original harness must have been replaced with a ’79 harness (which is severely butchered). I purchased a used ’77 harness off EBAY that seams to be in great shape. I’m laying it out on plywood to check everything and clean it up before I install it. In doing so I’ve discovered (with help from http://www.globalsoftware-inc.com/coolerman/fj40/DizzyFaq.htm) my distributor is a large cap ’81-‘87 unit with a ’78-‘80 igniter. I also noticed the alternator has a built-in regulator. When I initially tore down the vehicle eight years ago the wiring was so cobbled up I did not label many of the connections. I believe some of the dash switches may also be out of a ’79 because they don’t have matching connections to the ’77 harness. (hazard and wiper). Wondering if someone has diagrams/sketches on the following:

How do I connect the ’81-’87 distributor & ’78-’80 igniter to the ’77 harness?

How do I connect the alternator (w built-in regulator) to the ’77 harness? (instead of alt. terminals E & F coming from t he Regulator Ballast Resister I have Terminals L & G. )

The engine ran well when I purchased it but I'm not sure if the alt was working correctly.

77 harness.jpg

77 dizzy.jpg





Jun 8, 2012
Colorado Springs, CO
I have never seen a ballast resistor on a voltage regulator. Since the alternator is internally regulated it is not OEM, you need to tell us the manufacturer and model if you want help on that.
May 3, 2009
Does your harness plug for the alternator look like this? This is the back of a 77 alternator. With a separate firewall mounted voltage regulator.


You have a later alternator. Swap it out for a '77 model and you can avoid butchering your 77 harness. That's the easy and simple way.

If you just gotta hack then get the correct harness connector from coolerman.

That's a link ⬆︎ Go to the Alternator page & scroll down until you get to:

Two terminal female Alternator connector for INTERNALLY regulated alternators on 1979 to 1983 FJ40's

Spend some time with the wiring diagrams from both years and make up the new connectors for the alt and VR wires. Good luck.
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