Wiring help needed

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roadrunnerh

roadrunnerh

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Hello everyone,
I'm in the home stretch with my 383 project, and now tackling the wiring harness.
I've painstakenly removed, bagged and tagged several electrical items that will not be needed; fuel pacer, all EGR related equipment, etc.
I have been looking through my 1975 FSM like a madman. It's been taking me some time to fully grasp the wiring diagram I'm not ashamed to say. The harness is the original Slant 6 unit. With the big block swap, all I really needed to do was shorten some of the wiring to: Alternator, Coil, Distributor, Voltage regulator, Temp Sensor.
I'm planning on replacing main alternator wire with 10 gauge wire in preparation for higher than the stock 225 unit presently in the car. (No, I don't want to purchase a Powermaster alternator just yet)
I've been using Pico brand materials MADE IN USA, when possible. I used their butt joint crimp and heat shrink glue connectors that are amazing! I did a test on scrap wire - you can not pull these apart! I will be installing a Tach, Temp, and Oil gauges, so I will route wires in the harness neatly and tap into the fuse box - which seems much tougher on this A body than my 68 RR! The fuse box seems sealed? I was going to run a busbar inside the car under dash for power, lights, and ground for the gauges. In the old days, I would just tap into ashtray light for lights for gauges....
I really want to do this right, and I am open to suggestions, recommendations!
Where are the Forabodiesonly electrical gurus? Del - you out there?
Here's a pic of my mess, LOL
Scamp wiring mess.JPG
 
Sounds to me like you are on the right path. Do yourself a favor and make your own diagrams based on what you are doing especially for anything you add or change.

As for your "buss bar" idea, in my builds I used one of these;
https://www.amazon.com/gp/product/B00WM2MWQ4/?tag=fabo03-20

I really like this product because you have a ground, switched power and direct power connections. So you only have to run one wire from this box to a constant power source, one to a switched power source (fuse box) and ground it, then you can run anything you like off this box and it is fused.

I don't know how you are wiring the alternator, but I run a #6 gauge wire from the alternator to a resettable circuit breaker (get them at any local parts store), then run it to the battery. I am sure you have seen this website;
Catalog
 
The problem with OEM diagrams 73/ later for A bodies is they are drawn completely different and can be more difficult to follow depending on what you are doing. "Someone" around here offers colorized diagrams, I don't know if they are available for the later ones. If you don't have the MyMopar aftermarket two-page diagrams, they are NOT complete nor as detailed, but they are "old style" line drawings and can be easier to follow

What are you doing about the bulkhead connector and ammeter? Or is this an external shunt setup, might be? If you keep the ammeter, make certain it's in good shape and consider silver brazing the studs to the shunt

Other big problem with the old girls is fusing was never "enough." There are several circuits that can "burn down the house" and the main fuse link is just not enough. The 73/later stuff was a tiny bit better

A recurring issue in these old girls is the harness voltage drop from battery, through the harness, bulkhead, ignition switch, and back to regulator, and cause over charge voltage. Consider adding a relay triggered by IGN1 to feed the underhood ignition and VR loads
 
Thanks for the quick feedback guys!
70chall440, I was thinking about using something just like that. For lack of proper electrical nomenclature - I'll call it a sub panel for my car? LOL
Where would I tap in? Would this loosen the load on the factory setup?

67Dart273 said:
What are you doing about the bulkhead connector and ammeter? Or is this an external shunt setup, might be? If you keep the ammeter, make certain it's in good shape and consider silver brazing the studs to the shunt
Click to expand...
Del, I am keeping the original bulkhead. I'll be using all the factory gauges except oil light, and temp gauge. I would like to run both my Autometer mopar temp gauge AND my temp gauge in the dash but I am using a 65 SS HEMI water pump housing and have no more ports and don't wanna drill one.
What do you mean by keep the ammeter?
There's a lot more here that I don't know, than I do know!
 
67DART273 - can you explain how this would work - "Consider adding a relay triggered by IGN1 to feed the underhood ignition and VR loads"?
 
67Dart273 said:
The problem with OEM diagrams 73/ later for A bodies is they are drawn completely different and can be more difficult to follow depending on what you are doing. "Someone" around here offers colorized diagrams, I don't know if they are available for the later ones. If you don't have the MyMopar aftermarket two-page diagrams, they are NOT complete nor as detailed, but they are "old style" line drawings and can be easier to follow

What are you doing about the bulkhead connector and ammeter? Or is this an external shunt setup, might be? If you keep the ammeter, make certain it's in good shape and consider silver brazing the studs to the shunt

Other big problem with the old girls is fusing was never "enough." There are several circuits that can "burn down the house" and the main fuse link is just not enough. The 73/later stuff was a tiny bit better

A recurring issue in these old girls is the harness voltage drop from battery, through the harness, bulkhead, ignition switch, and back to regulator, and cause over charge voltage. Consider adding a relay triggered by IGN1 to feed the underhood ignition and VR loads[/QUOClassic Car Wiring . Com : Home of the original color laminated classic car wiring diagramTE]
Worth every penny.
Click to expand...
67Dart273 said:
The problem with OEM diagrams 73/ later for A bodies is they are drawn completely different and can be more difficult to follow depending on what you are doing. "Someone" around here offers colorized diagrams, I don't know if they are available for the later ones. If you don't have the MyMopar aftermarket two-page diagrams, they are NOT complete nor as detailed, but they are "old style" line drawings and can be easier to follow

What are you doing about the bulkhead connector and ammeter? Or is this an external shunt setup, might be? If you keep the ammeter, make certain it's in good shape and consider silver brazing the studs to the shunt

Other big problem with the old girls is fusing was never "enough." There are several circuits that can "burn down the house" and the main fuse link is just not enough. The 73/later stuff was a tiny bit better

A recurring issue in these old girls is the harness voltage drop from battery, through the harness, bulkhead, ignition switch, and back to regulator, and cause over charge voltage. Consider adding a relay triggered by IGN1 to feed the underhood ignition and VR loads
Click to expand...
Worth every penny.Classic Car Wiring . Com : Home of the original color laminated classic car wiring diagram
 
supertruck said:
67DART273 - can you explain how this would work - "Consider adding a relay triggered by IGN1 to feed the underhood ignition and VR loads"?
Click to expand...
These cars typically have some voltage drop through the harness from battery through ignition switch and back to ignition system/ voltage regulator. Because the VR sees low voltage, it ramps up the charge voltage which causes the battery to run high.

"Electrically" speaking you cut the "ignition run" (IGN1) line coming out into the engine bay and feed the firewall end to a relay coil. Feed the relay contacts with good heavy wire, breaker or fuse, from, say, the starter relay stud, and hook the load/ switched end of the contact to the other end of the wire you cut--which is the engine bay loads.

So far as the ammeter, I'm pretty sure your newer ammeter is an "external shunt" type meaning it does not use the old style heavy wiring. Look at the ammeter connections on your cluster. If they are small no18 or so wire, that iswhat you have.
 
roadrunnerh said:
Thanks for the quick feedback guys!
70chall440, I was thinking about using something just like that. For lack of proper electrical nomenclature - I'll call it a sub panel for my car? LOL
Where would I tap in? Would this loosen the load on the factory setup?
Click to expand...

So you need 3 lines

Ground - you can ground it anywhere but you need to make sure it is a good clean ground

Switched power - this could come from a variety of places but I would check the fuse box and see if there are any terminals that only have power when the key is on. It seems to me that there should be but I could be wrong. If not, then you need to tap into any circuit that is only live when the key is on (radio).

Constant power - same deal, check the fuse box first, if you can't find anything there then look at the cigarette lighter

As for decreasing the load, no this will not decrease the load because an electrical load is what it is, but what it does for you is give you a place to hook up all of the relatively modern stuff without hacking the crap out of the factory harness. Now, if you won't be running a bunch of add-on stuff then you might not need it.

BTW this is called a power distribution block, center or module. There are many different types, just google "blue seas power distribution center" and you will find them.
 
Can you guys verify this? The wire in the pic - Brown with light blue tracer (looks tan with blue tracer) lol.
Anyways, the one end I removed it from EGR Timer, the other end connected to the starter relay?
brown wire blue tracer 1.JPG
brown wire blue tracer 2.JPG
brown wire blue tracer 3.JPG

Should I just remove it?
 
It’s not that there are less people that can help, but maybe like me they are resisting complicating things.:D
I totally agree with Del, and know that this is in good hands.
 
Thanks TrailBeast! I put a lot of time into this car, so I want to do this right. I'm after a concise plan - kinda K.I.S.S. I am open to suggestions, so don't hold back. I need all the help I can get.
A good buddy recommended running a ruse right at the + battery cable, saying it will prevent catastrophe. It's not the "look" I'm after under the hood (think '68 Barracuda Formula-S 383) but I still may go that route.
Most importantly, I'm gonna decide quick because I want to get this motor FIRED UP real soon!
 
I'm an electrical retard. You don't WANT me in here. LOL
 
roadrunnerh said:
Thanks TrailBeast! I put a lot of time into this car, so I want to do this right. I'm after a concise plan - kinda K.I.S.S. I am open to suggestions, so don't hold back. I need all the help I can get.
A good buddy recommended running a ruse right at the + battery cable, saying it will prevent catastrophe. It's not the "look" I'm after under the hood (think '68 Barracuda Formula-S 383) but I still may go that route.
Most importantly, I'm gonna decide quick because I want to get this motor FIRED UP real soon!
Click to expand...

I don’t like it when a person asks a question and one of the first people answers it, only to have 30 more people chime in with opinions.

Anyway, I use a 30 amp self resetting breaker instead of fusible link for main cabin power feed right off the positive battery side terminal on the starter relay with fuses between that and my devices that need constant power.
(Stereo, amplified antenna, head and parking lights, overhead light, horn, and so on)
My headlights are powered with relays on the radiator support, so the headlight switch and dimmer only have the load of the relays switching and not all the load of the headlights.

Things that need key switched power come off the ignition switch main feed out of the ign switch.
(Ignition, relay for the sense wire of the voltage regulator, fuel pump, gauges power, electric choke and whatever else.)

Maybe you could use a main fuse inside under the dash if you want to use something more functional but don’t want it seen.
Some use those large cartridge style fuses like you see in some of the newer cars.
 
I can not find that connector roadrunnereth can you id it from your manual? Get on back behind the diagrams, there are connector charts.
 
TrailBeast said:
I don’t like it when a person asks a question and one of the first people answers it, only to have 30 more people chime in with opinions.
Click to expand...

Happens to me ALL the time here. S'why I've slacked off on answering some.
 
I cannot read those "good enough." But it almost looks like you are already there. The notes you have on the connector in post 19 so long as you identify those and confirm, I would EG remove battery ground then "continuity" them out to be sure.

Here's the problem..........I need 75/76 manuals to be able to follow all this because of the way they are drawn. You would have to follow each wire back through the diagrams

I've got a paper 75/76 but cannot locate it. Some of this stuff is packed away at the moment

Example you axed about the blue / yellow? Up in post 10? You need to find the starter relay (There's an index a page or two before the drawings) and get the wire number for that color, then follow it down through and see where it goes.
 
How do you tap into the fusebox on a '75? This is way different than on my '68. No spades to connect to. Solder onto a "fuse terminal" (clip at each end of fuse) and add a fuse?
I've got the Blue Sea fused distribution box installed, just need to figure out where to get "Ign On" power and a source for lights.
If I seem frustrated, please understand I'm so close and I am dying to start this car!
 
I have no experience with the late fuse panels, but I'd say "usual splicing methods" as you mentioned

"What fuse?" You talking about instead of a fuse link? Problem is this. It should protect the charging wire but if you upgraded the alternator to a monster, the alternator might cause th fuse to fail. "Figure from there." Fuse links nowadays are a problem because I know of no one who markets them in an "easily defined" package
 
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