My 79 had electrical problems a few years back resulting in me buying a new harness from a forum member. The connector that had all the alternator and carb wiring was different somehow than mine so I snipped it and made a new one. Everyting has always worked and still does, but I noticed a few days ago while poking around with my volt meter that I get a lot of strange readings on that plug.

Battery car off - 12.3v
battery idle- 13.6v
battery 3000rpm- 14.6v

alternator car off ring terminal- 12.3v
alternator idle ring terminal- 13.8v
alternator 3000rpm ring terminal- 15.3v (biggest concern)
white wire- negative 0.02v
black/yellow wire- 7.5v
yellow/black wire- same as battery

I checked continuety from the white wire to the end of the harness and it is unconnected yet still reads voltage and coninuety to the regulator plug. Does it tap into another wire? I'm assuming it is a + wire.

Is any of this normal? Is it miswired or a bad regulator? I've put 9000 miles on it like this and no issues. Just strange readings. Any help is appreciated.

 

The regulator acts like a dam, considering it going out of range I'd suspect the regulator

 

If it was miswired would it read 15.3v at idle too? Not just under load? What about the negative voltage? Is it supposed to drain 0.02v like that?

 

what would lead you to suspect mis-wiring?

not sure of your options/add ons on the car. The clock in the dash would have a draw, aftermarket stereo perhaps for the clock and stations

 

I had to rewire it when I swapped a new harness in. The connectors didn't match up on the alt/emission plug. So I made new connections for the alt and water pump sensor. Emissions is removed. There is a white wire that is loose going nowhere and a contenuety test indicates it leads to the white wire coming from the back of the alternator. This wire shows a 0.02v draw and somehow has contenuety to another wire on the regulator. The small black wire I believe. Yet when I connected the two together it blew my engine fuse...

Basically what I'm askining for here is what wire goes where on the regulator plug. A pinout if you will. The fsm diagram is useless.

 

ah so suggesting the schematic would not help

ok this is what the plug would look like going into the back of the alt
sorry camera is nto the best but should do

 

Thats how mine looks but what about the sub harness connector for the emission/alt harness? Maybe mine is different bc it was an early (78) build. The schematic is useless because it does not match and i dont know why. Its frustrating...

 

are you keeping this SA stock?

 

Mine is a 4/78 and the picture is of a 3/78 harness
If you referring to the other end it would need to be cleaned to see the colors