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Discussion Starter #1
I’m in the process of requiring my 1967 el Camino with a painless wiring harness. I discovered a little box behind the battery mounted to the core support, that looks like it connects to a pigtail coming from the positive battery cable. After some research I discovered it was a battery junction box. I tried looking it up but I couldn’t find what it’s for/ how it works anywhere. Some generic explanations said that it provides power to all the accessories but this doesn’t make sense to me, as there is only one connection point, for the pig tail coming from the positive cable. My question is how does the junction box work, and do I need it for the install of my new harness? Any advice is appreciated.

Some background info:

The car went dead a few months back, I had just got it running for the first time in 20 years with some basic maintenance: oil change, new battery, stuff like that. It over heated so I had to tow it home and I tried to jump start it, but I switched the positive and negative cables cuz I’m an Idiot :( either that must have fried something or something got fried when the car over heated because after that it was completely dead: wouldn’t start and nothing electrical worked. I tried some stuff like replacing fusible links but nothing worked, and I eventually decided to just redo the whole wiring harness because it could probably use it anyways and hopefully the problem would be fixed after that

my new wiring harness is a painless part number 10104

any advice is greatly appreciated, this is my first project car and I’ve got a lot to learn from it.
 

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Do you have a good multimeter or test lamp? Use it to probe and trace wire power from the battery through each component. When you lose power, stop and fix that problem. Begin the trace again towards the next component. Yes, this is tedious but you must be very methodical and deliberate to chase wiring gremlins.

Without a picture, I think you are describing either the horn relay on the radiator core support or maybe the voltage regulator.

Rick
 

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Discussion Starter #4
the positive battery junction block is usually where the
Horn Relay, Charge Wire, and Fusible Link to the Battery tie together..
and that's where most everything else gets power, except the big starter cable..

remember this thread ??
1967 El Camino won’t start
Hi JJ. Yes I do remember that thread, thanks for all the help! I guess why I’m confused about is how the charge wire and fusible link connect together at the junction block, sine it only has a single post for the battery pigtail, and my painless wiring manual doesn’t seem to mention it at all. If I remember right you told me that the junction block connected the horn relay and then a bunch of other accessories in my old thread, but this kit has an included horn really on the fuse block.

here’s a picture of the junction block.
129353

And here’s some pictures of my wiring in progress:
129354
129355
129356
129357
129358
 

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as said the diagram don't show the fusible link,
it goes between the junction block and battery
like this Link> Mad Chevy Main
some good readin there too..

also the horn relay power side is a Buss Bar too, just like the junction block
for connecting all the power together.. that's how they all tie together..

heres the pic with the junction lock in red and the charge wire in purple,,
you can see how they all tie together with the junction block and buss bar..
you can see all the other things tied to the other junction for the charge wire..

the painless wiring kit may have a whole lot of changes built into it,
to spread some of that power around thru more wires..
also post a link to the Painless kit or part number,
we may be able to see the instructions online..

66-2 JunctionBlock.jpg
 

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@JJLT1
JJ does it look to you like a previous individual did a lighting circuit upgrade.
In the third image down in post above, it looks like if a wire runs from pos on battery to the junction just in front of the battery box, that it is giving battery power to the headlights.
 

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Discussion Starter #7
as said the diagram don't show the fusible link,
it goes between the junction block and battery
like this Link> Mad Chevy Main
some good readin there too..

also the horn relay power side is a Buss Bar too, just like the junction block
for connecting all the power together.. that's how they all tie together..

heres the pic with the junction lock in red and the charge wire in purple,,
you can see how they all tie together with the junction block and buss bar..
you can see all the other things tied to the other junction for the charge wire..

the painless wiring kit may have a whole lot of changes built into it,
to spread some of that power around thru more wires..
also post a link to the Painless kit or part number,
we may be able to see the instructions online..

View attachment 129361

Hey JJ, here's a link to the painless manual. on page 47 there's a charge/ battery schematic, which includes an "inline fuse holder," is it possible this is the upgraded equivalent of the battery junction box? it appears to give power to the fuse block, in turn giving power to the accessories. (side question, it says the MIDI fuse connects to the inline fuse holder, is the MIDI fuse possibly the pigtail coming out of the battery + cable that used to connect to the junction box?
Here's the link: painless performance wiring manual 10104
here's a pic of that schematic:
129365
 

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yes
the new MIDI fuse and inline fuse holder replace the junction block and fusible link at the battery..
but the new horn relay on the fuse box WILL-NOT have the buss bar, its just for the horn..

there will be a few splits in the main power,, as you said to the fuse box which will get
all the time / un-switched battery power,, [ and switched power from the ignition switch later ]
then one to the ignition switch,
and one to the head light switch, [ good time for the headlight relay up-grade ]
and the Charge wire connects to all these.. [ thru those old junction blocks / buss bars ]
all these can be Fused individually too, or use Circuit Breakers .. lots of choices..

and up to you for later up-grades, for a accessory drop under the hood and / or in-cab,
could be battery power or key-on power or both..

what kind of Alternator are you using ??
is it the original External Regulator ??
[ I don't see the regulator, usually on the driver side core support ]
its a very good time to up-grade to the newer Internal Regulator,
better control / less wiring / fewer problems / easy-er to find and replace ,,
Internal Reg is what they are showing in your pic above, with just 3 wires..
 

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Discussion Starter #11
It's good to know I'm not missing anything super important in terms of that junction block, thanks, guys! I did upgrade to an internally regulated alternator, which should make wiring a lot easier. what exactly is a headlight relay up-grade? would it involve replacing the headlights? or just adding a relay instead of having the wires routed directly like they are now? and sorry to change the subject but I was working on the ignition wiring yesterday and thought it would be a good idea to upgrade to an internally resisted coil. if I did that would the yellow ballast bypass wire going to the starter no longer be needed?(shown below)


129394
 

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what exactly is a headlight relay up-grade? would it involve replacing the headlights?
or just adding a relay instead of having the wires routed directly like they are now?
no don't have to change headlights..
its just moving the load from the whole light wiring harness to just the
relays at the headlights.. saves the switch, dimmer, connections
and gets more volts to the lights = brighter lights..
elec HL relay1.jpg


I was working on the ignition wiring yesterday and thought it would be a good idea to
upgrade to an internally resisted coil.
if I did that would the yellow ballast bypass wire going to the starter no longer be needed?
are you still running a Points Distributor ??
you may be able to save the original Resistor wire from the Ign Switch
to the +Coil, and it will look stock, and don't need the extra resistor..

the Coil Power Resistor and Yellow Ballast Bypass wire do the opposite..
the resistor cuts the voltage 6-9v to the coil,
so the coil wont overheat for normal running,, and points last longer..
and the yellow bypass adds voltage 12v while cranking for a hotter spark
while the motor is cold and lean..

or swap to a HEI and run it on 12v..
there are some Small Cap HEI's too, that look more original..
.
.
sorry I missed the part number in the first post, thanks for the link,,
man that's a lot-a-readin.
they do go over the Headlight Relays and other things
same as the Mad Elec Site..
both have good pics for learnin.. I saved a few of those..
 

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Discussion Starter #13
Hey JJ,
I'll definitely look into that headlight relay upgrade, it seems simple enough and I definitely can't complain about brighter headlights. Yes, I'm still running points on the car, but I did go ahead ad buy a new coil, my guy at the store recommended it because it's resin-filled whereas my old one was oil, and I think it still looks pretty stock. However I do eventually wanna upgrade to a pertronix ignitor 3, it basically has the functionality of an MSD, including multi-spark and a rev limiter, but looks completely stock. That painless manual def has some good reading, I think I must have read through it at least 3 times by now. So if I'm understanding right about the coil, the yellow bypass wire is no longer needed because there's no balls to bypass?
 

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Discussion Starter #15
the new coil is a pertronix flame thrower, if i remember right it is an HEI could, i think capable of up to 40k volts, but I'm not sure. down side is it only works with stock points or the ignitor 1, so i will end up upgrading it as well when i get around to installing an ignitor 3 electronic ignition.
 
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