Searching for 12v switched power after ditching ballast and installing aftermarket electronic ignition

[mshred]

So not technically an a-body, but I am hoping to get some assistance here since the concept is similar...

I have been going through the harness on my 1977 Aspen wagon, removing parts of it that I don't need, and ensuring that all the wires and connections are good and clean as this is going to be a regular family hot rod in the warm months. I have converted to a Mallory electronic ignition box, so following an electrical service manual (for 1976 unfortunately) I have been able to remove what appears to be wires no longer needed (factory ignition box, exhaust recirculation module, ballast resistor) but I am keeping the factory ammeter in place and working as is. In the process, I have also added a small fuse block in the car to give switched power to my tach, the Mallory box, and my stereo deck so that everything is in one place and nice and clean.

I am looking to add switched power, via a relay, to power the fuse block in the car (pictured below). I am looking for suggestions on where I could pick up switched 12v power without getting overly complicated. I had thought there may be a terminal on the starter relay (pictured) where I could get switched 12v from (all I will be using on this relay is "I" for ignition, "G" for ground, and the main stud to send power to it) but from what I understand none of the terminals would do that. I am planning to use a 40-50amp relay from said 12v switched power source even though I know those 3 accessories won't need that much amperage.. However it would be nice to do it this way from now in case I decide to add other small circuits to it (i.e. line lock, trans brake, etc.) at a later date.

Looking for some suggestions on how to do this, and maybe what others have done. Also, I am currently using the stock monster starter, but may be converting to the late model mini starter...not sure if that would affect any of this or any of my other wiring.

 

[Professor Fate]

By "switched 12v", are we to assume you're looking for hot in run AND start? Or just in run?
The ignition switch (which I assume you're still using) does not have an output that is hot in both run and start, they are two separate circuits- "IGN1" (run) and "IGN2" (start). When adding aftermarket ignitions (or in your case, a relay) these two feeds are generally connected together to supply a "constant" switched 12v source.
But since you have already sliced and diced your harness, you may have eliminated one or the other already- you'll have to go back and reinstall one or the other if necessary. If you have eliminated the ignition switch (running switch functions through a toggle panel), you'll have to figure that out on your own dependent on how you rewired the thing.
NOTE: IGN2 is hot in start- but it is NOT the starter circuit and is not run off the starter relay. Running your ignition off of the relay could cause backfeed issues that do not allow the starter to disengage, and can introduce other wonky quirks into the system.
And that really looks like an MSD box, not a Mallory.

 

[mshred]

By "switched 12v", are we to assume you're looking for hot in run AND start? Or just in run?
The ignition switch (which I assume you're still using) does not have an output that is hot in both run and start, they are two separate circuits- "IGN1" (run) and "IGN2" (start). When adding aftermarket ignitions (or in your case, a relay) these two feeds are generally connected together to supply a "constant" switched 12v source.
But since you have already sliced and diced your harness, you may have eliminated one or the other already- you'll have to go back and reinstall one or the other if necessary. If you have eliminated the ignition switch (running switch functions through a toggle panel), you'll have to figure that out on your own dependent on how you rewired the thing.
NOTE: IGN2 is hot in start- but it is NOT the starter circuit and is not run off the starter relay. Running your ignition off of the relay could cause backfeed issues that do not allow the starter to disengage, and can introduce other wonky quirks into the system.
And that really looks like an MSD box, not a Mallory.

Hot in run and start.

Yes, still using factory ignition switch, there are no toggles for anything.

The only wires I removed ran from starter relay to either ballast resistor, EGR recirculator, or the factory electronic ignition box, nothing to the actual bulkhead connector was removed removed from the harness. The starter relay I have pictured only has "I" for ignition", "G" for ground, "BAL" for ballast (which I removed), "EGR" for exhaust gas recirculation (which I removed), "SOL" which never had anything if I recall correctly (or maybe because the harness is out of the car I am not recalling what goes there), and the power stud. How would I connect run and start using this type of starter relay? Would the BAL be IGN 2? Electrical is something I diving into as new territory, so explain to me like im a 5 year old

And its definitely a Mallory box. I don't know of any MSD box model that ends in an "E" as seen in the pic, other then the Mallory hyfire 6al that is pictured, but maybe I need to learn to the read the parts I have before learning electrical?...LOL

 

[4mulas]

Not sure what colour it is on the 77 aspen but the older mopars it would be the blue wire that went to the ballast you just eliminated. Whichever one fed the ballast is what you’re looking for.

 

[mshred]

Not sure what colour it Simon the u& aspen but the older mopars it would be the blue wire that went to the ballast you just eliminated. Whichever one fed the ballast is what you’re looking for.

Not sure I fully understand....the blue wire that went to the ballast has what function?

 

[Professor Fate]

Blue wire is only hot in "run". IGN2 (normally a brown wire) is "start". They need to be connected together to supply 12v in both start and run positions.

 

[4mulas]

Not sure I fully understand....the blue wire that went to the ballast has what function?

It has the function of what you’re looking for. 12v switched power.

 

[Professor Fate]

It has the function of what you’re looking for. 12v switched power.

He wants hot in start AND run. The blue wire is only hot in Run- it goes dead in Start.

 

[mshred]

Blue wire is only hot in "run". IGN2 (normally a brown wire) is "start". They need to be connected together to supply 12v in both start and run positions.

As in a jumper from one terminal on the starter relay, to the other?

It has the function of what you’re looking for. 12v switched power.

So the wire that fed the ballast, which would be going to "BAL" on my starter relay would be switched 12v power...But I need hot in both run and start since the ignition box needs power in start to fire the car.

 

[Super-Cuda]

Not sure of the color coding but wouldn't the radio wiring be a 12v switched circuit?

Should work if you are only using the power to switch on relays.

 

[Professor Fate]

As in a jumper from one terminal on the starter relay, to the other?

So the wire that fed the ballast, which would be going to "BAL" on my starter relay would be switched 12v power...But I need hot in both run and start since the ignition box needs power in start to fire the car.

Quit trying to overthink this.
Where the ballast was, there should be 2 feed wires- one blue, one brown (confirm the colors in your FSM, I'm using the colors normally associated with A bodies; but yours should be similar).
These are your IGN1 and IGN2 wires. (green circle/arrow)

Remove the ballast connectors and strip the ends of the wires, and connect them together- crimp, solder, whatever. Then connect that to your proposed relay trigger wire. Done.
DON'T eliminate any of the blue wire or connections/splices to it, as this wire also feeds other circuits to the alternator, voltage regulator, electric choke, etc.

 

[Professor Fate]

Not sure of the color coding but wouldn't the radio wiring be a 12v switched circuit?

Should work if you are only using the power to switch on relays.

It's not hot in start.

 

[Kendog 170]

 

[mshred]

Quit trying to overthink this.
Where the ballast was, there should be 2 feed wires- one blue, one brown (confirm the colors in your FSM, I'm using the colors normally associated with A bodies; but yours should be similar).
These are your IGN1 and IGN2 wires. (green circle/arrow)
View attachment 1716257767
Remove the ballast connectors and strip the ends of the wires, and connect them together- crimp, solder, whatever. Then connect that to your proposed relay trigger wire. Done.
DON'T eliminate any of the blue wire or connections/splices to it, as this wire also feeds other circuits to the alternator, voltage regulator, electric choke, etc.

Okay, going to try and get this figured out in the garage tonight. I can't remember if I kept the old wires that I removed. Here I was removing wires thinking they would be useless, even for this use scenario...oh boy lol

 

[Dana67Dart]

A starter relay might not be the best option.

It is designed for short bursts rather the continuous duty

 

[mshred]

A starter relay might not be the best option.

It is designed for short bursts rather the continuous duty

Funny you mention that, because before I posted this thread I was doing some digging and it seems to not be recommended to use the starter relay in this way. I mean, if it could be used, that would be awesome and simplifies things, but if not, then where could I pull 12v ignition power from?

 

[Mattax]

First.
You have a '77 Aspen. Many things you may have read about 'all' A-bodies, even if generally true, are different and do not apply to a '76 A body or a '77 F-body.

Second.
There is nothing on the older starter relays that would be useful for your purposes. The starter relay's stud serves as a junction in the battery feed. All the other connections are only for starting.

--------------------------
My suggestion is to (hopefully) reconnect the factory wiring. Then place a piggyback on the ballast resistor terminal for the on/off trigger of the Mallory box. If the box is a CD ignition, then the ballast resistor itself is not needed - so you could do a jumper. On the hand, it probably doesn't hurt to leave it if its simpler. Only a tiny amount of current goes through it when used for telling a CD box to be on.

I don't have a '77 FSM or diagram. But if its anything like the '76 wiring, the power feeds (alternator and battery) are joined in the engine bay, and the main feeds off of them are branched off in the engine bay. The basic concept of the main circuits remained the same (in '76) as previous years.
Ignition 1 (Wires labeled J2) is on with key in run
Ignition 2 (Wires labeled J3) is on with key in start. Starter relay wire from the key switch is also hot with the key is start (but not directly connected to J3).
Switched Accessory is on with key in run or accessory.

This is an overview of the '76 A-body main circuits.

 

[Mattax]

With a Hyfire on a '73, it could be wired liked this with the 12 V switched on connected to any location on the J2 or J3 circuit - as long as they are still connected together. The J2 and J3 connect through the 1/2 ohm resistor. The 5 ohm resistor - if still used in '77 for the first gen. ECUs - will likely be too much resistance for the Mallory to turn on.

The 12 V switched wire simply triggers are relay inside the box. The power to run the box and coil comes from the heavy wire connected to the main battery feed. This could be at the starter relay junction (simplest) but will cause the ammeter to indicate slight battery charging. If the current draw is an amp or two you won't even see the needle move.

On a '76 as you can see in the previous post, the battery feed and alternator outputs join in the engine bay. The ammeter wires are tiny because its a remote shunt ammeter. The ammeter indicates flow based on the tiny amount of current running in parallel to the shunt. However the information displayed is the same. if you connect the Mallory's main feed at the starter relay junction, the ammeter will sense current going from the alternator to the battery - even though it doesn't actually go to the battery. Check the the instructions and if its under 5 amps it probbaly will barely move the needle. Or you could attach at the alternator's output stud.

 

[mshred]

Thanks for your reply. I agree that this is not an A-body, and I know things are different, but the input is what I was after.

In terms of a trigger, I need a trigger for the auxiliary fuse block I installed, not just the CD ignition system. I am aware that the heavy red and black are what actually power the Mallory box, but I still need switched power for it and the other circuits I am running off the fuse block. Is what you are suggesting as a trigger to be used to trigger the fuse block?

The only wires I have removed are in the engine harness, and those attached to ballast and electronic ignition. Nothing from the actual ignition switch inside. I will take a look at my bulkhead and find the ignition run and start wires and join them (Assuming they are the ballast wires as mentioned earlier by Professor Fate.

For reference, here is a pic of the ballast resistor in the car before removing the harness

 

[Mattax]

One of those resistors is 0.5 ohms. One is 5 Ohms.
The Ignition start wire (tradtionally J3 and brown) connects to the 0.5 ohm resistor. The branch going to the coil will no longer be used for the coil -so that's an easy place to connect any low current circuit that must be on with the key in run and start positions. Of course the J2 & J3 still need some sort of connection whether its a 1/2 ohm resistor or a jumper or whaterver. if its not engine related, then connect to the switched accessory circuits. There may even be extra fuse cavities available in the fuse box.

The engine harness:
On a 1976 A-body the engine harness is where all of the connections are made to the main circuits.
Study that drawing until you see the connections.
Take your finger and trace the power path to from the alterntor to the battery. Then the alternator to the headlight switch. Then alternator to the key switch.
This is very different than the standard A-body wiring from '66 to '74.
Also notice there's a fusible link on each of the main feeds. The junctions are splices - probably welded.

here's a photo from the WWW that I marked up.

I would add any new electrical items that will be used with the engine running to the alternator output. This keeps the maximum load through the fusible links to the factory maximum.

 

[Kendog 170]

You could add a fusible link then an appropriately sized wire to feed the new fuse panel at the relay

 

[Mattax]

Then how would he know if the battery is charging?

 

[mshred]

Ok so I think I have this figured out. First pic shows the only wire that comes to the starter relay from inside ignition switch which is the yellow going to "I" for ignition on the relay

Next is the brown wire that goesto the "bal" terminal on the relay, that when traced to the ballast resistor, is joined with the coil wire and therefore considered J3 (you can see me holding the cut brown coil wire) and thus ignition start.

Lastly, the blue wire I am holding in the last pic would be J2, ignition start. This is the wire that is connected to a whole bunch of others that goes to the alternator. I will recomnect it back where I cut it from

So now, the plan is to join the brown J3 wire to the blue J2 wire with a butt connector, and use the cut brown coil wire from that splice as the feed to my relay that will power the fuse block (pic below). The mallory box itself will get heavy power from the battery post of the starter relay

Let me know if this is making sense and would work. I tried to digest everything mentioned here, along with cross referencing my fsm for the wiring. This should give me the power to feed to relay switched in run and start (I hope). Hoping these pictures make some sense.

 

[Mattax]

Ok so I think I have this figured out. First pic shows the only wire that comes to the starter relay from inside ignition switch which is the yellow going to "I" for ignition on the relay

Next is the brown wire that goesto the "bal" terminal on the relay, that when traced to the ballast resistor, is joined with the coil wire and therefore considered J3 (you can see me holding the cut brown coil wire) and thus ignition start.

That's possible. Sounds vaguely familiar but I can't claim to know for sure. Operationally the J3 is probably getting power when the relay is triggered by the S2.

 

[67Dart273]

To add a little bit, this is not magic, and I AM NOT FAMILIAR with Aspens

NORMALLY, in the older cars covered by this board, the IGNITION SWITCH is the key to it all

IGN1 is hot ONLY in run and goes COLD in "start."

The start voltage is provided by the brown / bypass circuit that comes from IGN2 If the Aspen has this, you can tie them together for aftermarket ignitions. If you are using ANY ignition that uses a BALLAST, the brown goes to the coil + side of the ballast

THERE ARE a couple/ 3/ 4 ways around this IF you cannot identify IGN2 or perhaps it does not exist? in Aspens

1...As mentioned, convert to the later Jeep style starter relay with the extra terminal. That extra terminal "acts" like IGN2
2...You can parallel the coil of a Bosch auto relay to the starter relay coil, and use that relay to provide the IGN2 function
3...You can use a large diode, AKA about 5A at 25 or more PIV from the yellow start wire to "act" like the ign2. Other end of the diode goes to coil + (if ballast) or jumper to IGN1 (if no ballast) The "bar" end of the diode goes to the coil + or in other words, "away" from the relay