Alternator wire going to the battery.

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Byron Gray

Byron Gray

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I am still figuring out what all the pervious owners of my car did. I'm dealing with the charging system and I noticed someone spliced a wire into the blue wire for the alternator that goes straight to the battery. No idea why they would do that and dose anyone know what or why? Thank you.
 
My bet would be the bulk head connector is melted and they did a bypass. Look up the MAD wiring bypass and it may help you. It's a know problem with these cars.
MAD Bypass Question
 
Possibly sliced into it for electric choke??? Keep in mind that I'm not great with electrical, kinda remember reading a thread about someone doing that .
 
There is actually 2 field wires for 70 and up charging systems. The green wire is supposed to go from one field to the (F) terminal of the regulator. The blue wire is supposed to come from the bulkhead connector and is supplied by the ignition switch. I have attached a diagram for my relay modification that will keep the lights from flickering (this caused by dirty/worn ignition switch contacts and is likely the reason someone ran a wire directly from the field to the battery). It is not a good idea to leave the field connected to the battery because if you had a short on it it could cause a fire. I would suggest you buy the relay (CHEAP FIX) and wire it up per my diagram. Let me know if you have any questions.
Charging system relay modification (2).jpg
 
superchargeddrt said:
There is actually 2 field wires for 70 and up charging systems. The green wire is supposed to go from one field to the (F) terminal of the regulator. The blue wire is supposed to come from the bulkhead connector and is supplied by the ignition switch. I have attached a diagram for my relay modification that will keep the lights from flickering (this caused by dirty/worn ignition switch contacts and is likely the reason someone ran a wire directly from the field to the battery). It is not a good idea to leave the field connected to the battery because if you had a short on it it could cause a fire. I would suggest you buy the relay (CHEAP FIX) and wire it up per my diagram. Let me know if you have any questions. View attachment 1715327834
Click to expand...
Ok when im home later I will look at mine more and see about the blue wire is still there it dosent look like it had been messed with. Just that separate wire added into it going to the battery. I replaced the voltage regulator I'm going to add a ground strap to it and my connection to the regulator im going to replace it's a little worn. I will look into trying out what you have done.
 
Byron Gray said:
I am still figuring out what all the pervious owners of my car did. I'm dealing with the charging system and I noticed someone spliced a wire into the blue wire for the alternator that goes straight to the battery. No idea why they would do that and dose anyone know what or why? Thank you.
Click to expand...

The blue wire was originally switched "ignition run" power. that power originally came from the IGN1 "run" contact on the ignition switch, through the bulkhead, and branched off to feed ignition, the VR, alternator field, and depending on year/ model, some smog devices

By jumpering that blue to the battery, the alternator field is ALWAYS powered and not switched. I'm suprised the battery does not go dead over time.
 
67Dart273 said:
The blue wire was originally switched "ignition run" power. that power originally came from the IGN1 "run" contact on the ignition switch, through the bulkhead, and branched off to feed ignition, the VR, alternator field, and depending on year/ model, some smog devices

By jumpering that blue to the battery, the alternator field is ALWAYS powered and not switched. I'm suprised the battery does not go dead over time.
Click to expand...
Yes I see that from my diagrams and my car dosent have smog it's far from stock.. I'm wondering other then what was already mentioned above why someone would do that. I can try to remove it and see if the car works fine.
 
ok so I looked at my wiring and what i thought was a wire going to the battery I was wrong. It turns out who ever wired the fuel pump into the blue wire of the alternator. and the wire I first thought is power for my MSD box. So i hate who ever wired this car a little more now and thank you guys for your help and information. It will help later on with this car.
 
OK here is the thing......THERE IS ONLY ONE "switched power" wire in the engine bay from the ignition switch, and that is IT. Bear in mind there are several "things" here..........

1....that wire IS NOT FUSED originally
2....that wire may already be overloaded from age and other deterioration to the switch/ connectors/ bulkhead connector/ old wire terminals etc and suffer voltage drop.

One way "around" the situation is to electrically ferret out the "run" wire coming out of the bulkhead and cut it. Run the bulkhead connector end you cut to trigger a bosch relay, and take power fused or breaker added from the "big stud" on the starter relay, and then reconnect the engine bay end of the cut wire to the switched contact of the relay

This not only will increase the power capacity of that circuit, but will help eliminate voltage drop problems which if present, will cause OVER CHARGING of the voltage regulator

Also depending on how much power the fuel pump draws, it should have a relay as well

Your MSD "small red" is in fact a "trigger" wire similar to a relay and doesn't draw much current. That is why MSD calls for the "big red" and "big black" to have a good solid voltage source---direct to the battery/ starter relay stud
 
Not much to add here.
But its worth mentioning.
A fair amount of small but sometimes important differences in the wiring of these cars.
Talking factory wiring.
So its always helpful to mention or have in a signature at minimum the model and the year.

Checking the service manual diagrams like it sounds like you are is always helpful.
Its often helpful then to make a schematic of the circuit(s) you're interested in. Especially so with some of the 70s wiring diagrams that use connection points that we, the readers, have to then use to assemble the drawing segments.
PS. Once in a while you'll find a mistake - even in the factory diagrams.
 
Thank you all for the input I will take and use with fixing this car the right way. Electrical is my weak spot when it comes to these cars but I am not one for short cuts or quick fixes.
 
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