Wiring issue with voltage regulator

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Rassnasty82

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So, redoing my harness with a donor one but the wires do not fully match up. I am trying to figure out where the blue wire that normally would come off of the alternator goes? I have a full msd ignition if that makes any difference? Any help would
Be appreciated

image.jpg


image.jpg
 
Are you gonna tell us the year/ make and model of the car you are working on or are we going to have to beat it out of you?

The blue VR wire must go to switched ignition
The green VR wire must go to one terminal of the alternator field

That flat VR is 70/ and later. That means you must use an alternator with an isolated field, IE 2 field terminals. One terminal goes to the VR green, the remaining one hooks to switched ignition

IF YOU ARE USING the original type wiring it is imperative you check for voltage drop With key in "run" and engine off, connect one meter probe to the blue field wire on the alternator. Connect the remaining probe of your multimeter to battery positive. You should read very little, the less the better, Anything more than .3v or so (3/10 of one volt) you need to address this. One good way is to use the "ign run" feed coming into the engine bay to feed a relay, and use the relay to control the engine bay IGN loads.
 
Yea seen that as well but nothing I can find explains exactly where the blue wire goes. One diagram I found shows it goes to ignition 1?


This doesn't explain it?

Dual_Field_Alternator_Wiring.jpg


There are two IGN feeds coming into the engine bay. One is the brown bypass circuit IGN2 and it's only hot for starting

The other is IGN1, normally blue AND IS THE ONLY source of switched ignition power coming into the engine bay

The wire from ignition switch going to the top of the ballast is indeed IGN1
 
Are you gonna tell us the year/ make and model of the car you are working on or are we going to have to beat it out of you?

The blue VR wire must go to switched ignition
The green VR wire must go to one terminal of the alternator field

That flat VR is 70/ and later. That means you must use an alternator with an isolated field, IE 2 field terminals. One terminal goes to the VR green, the remaining one hooks to switched ignition

IF YOU ARE USING the original type wiring it is imperative you check for voltage drop With key in "run" and engine off, connect one meter probe to the blue field wire on the alternator. Connect the remaining probe of your multimeter to battery positive. You should read very little, the less the better, Anything more than .3v or so (3/10 of one volt) you need to address this. One good way is to use the "ign run" feed coming into the engine bay to feed a relay, and use the relay to control the engine bay IGN loads.
So use the ballast to connect the Blue wire to the ignition switch and to the alternator? Sorry it’s a 1969 big block barracuda but has some newer model parts. I do have a brand new older version voltage regulator
 
This doesn't explain it?

View attachment 1715544759

There are two IGN feeds coming into the engine bay. One is the brown bypass circuit IGN2 and it's only hot for starting

The other is IGN1, normally blue AND IS THE ONLY source of switched ignition power coming into the engine bay

The wire from ignition switch going to the top of the ballast is indeed IGN1


Ahhh so splice the blue wire into the blue coming out of the harness. Ok that makes sense.... thanks
 
This doesn't explain it?

View attachment 1715544759

There are two IGN feeds coming into the engine bay. One is the brown bypass circuit IGN2 and it's only hot for starting

The other is IGN1, normally blue AND IS THE ONLY source of switched ignition power coming into the engine bay

The wire from ignition switch going to the top of the ballast is indeed IGN1


This the connection that is supposed to go to the ballast? It looks identical to the one coming from the firewall

image.jpg
 
The ballast has one end blue wire originally. That is switched ignition run or IGN1. The other end has a brown and whatever color went to the coil+ That brown is IGN2. You must jumper IGN1 and IGN2 together and use both of them for the "run" feed, and to the VR and field. That junction is where I was talking about "think about installing a relay. Use the junction of the blue/ brown to trigger a relay. Ground the coil, or feed it through an unobtrusive switch to ground for a simple anit-theft.

Feed the relay power from a fuse/ breaker off the big stud on the starter relay. Take the load end and connec that to all your underhood loads,......the MSD "small red", the VR blue, the field blue, and so on.

THE REASON you must connect the brown/ blue is that IGN1 "run" GOES DEAD during cranking. Originally the coil was supplied power by the brown, which is hot "in start" This is NOT the same as the yellow start wire, the two are separate switch contacts.
 
The ballast has one end blue wire originally. That is switched ignition run or IGN1. The other end has a brown and whatever color went to the coil+ That brown is IGN2. You must jumper IGN1 and IGN2 together and use both of them for the "run" feed, and to the VR and field. That junction is where I was talking about "think about installing a relay. Use the junction of the blue/ brown to trigger a relay. Ground the coil, or feed it through an unobtrusive switch to ground for a simple anit-theft.

Feed the relay power from a fuse/ breaker off the big stud on the starter relay. Take the load end and connec that to all your underhood loads,......the MSD "small red", the VR blue, the field blue, and so on.

THE REASON you must connect the brown/ blue is that IGN1 "run" GOES DEAD during cranking. Originally the coil was supplied power by the brown, which is hot "in start" This is NOT the same as the yellow start wire, the two are separate switch contacts.


Ok so looking at these two connections, the one with the blue and brown should be the ignition 1 and 2 correct? Then run a wire from the vr and the small red msd to
The ballast? Does it matter which side of the ballast each goes on? Sorry, wiring is like Chinese to me
 
those look like the original ballast plugs... an ohm meter is helpful in tracing wiring
 
those look like the original ballast plugs... an ohm meter is helpful in tracing wiring

I have one so I’ll use it, but if they are the original, then that makes it easy to just connect the small red, and one blue wire from the VR, and one blue wire from
The alternator just like the illustration.... man I love you guys!!!! Such an amazing community
 
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