1966 chevrolet cable junction box - Impala Tech
Electrical & Wiring Troubleshooting electrical problems

 
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post #1 of 8 (permalink) Old 06-15-2020, 07:51 PM Thread Starter
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1966 chevrolet cable junction box

Good Evening,

Looking more for an explanation, for months I have not been able to keep a charge on the battery. I had a constant live positive battery cable. Changed the ignition switch (original) thinking that the tumblers were worn so much the current wasn't cutting off. I then changed the voltage regulator (would click when key was turned). Did not fixed issue. I stumbled on the battery cable being pretty frayed and an additional wire that goes to a cable junction box.

My question is what is the purpose of the cable junction box?

I did replace the frayed cables and the car has held a charge all day, prior to this the battery would be dead in 15 mins.

Any explanation of cable junction box is appreciated.

John
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post #2 of 8 (permalink) Old 06-16-2020, 08:47 AM
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Garage
Electrical issues are my least favorite but you should start here:
Mad Electrical

Mad Electrical has a wealth of tech info on early 60's GM cars.

1969 Impala convertible build thread here:
https://www.pro-touring.com/threads/...ghlight=impala
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post #3 of 8 (permalink) Old 06-16-2020, 12:30 PM
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I might add that these cars are expensive enough already to buy parts for. You should take a second to trouble shoot to see what the issue is before you start throwing money at buying parts you do not need, AND often are of lower quality than the OEM part.

I would need you to dedescribe what you are calling a cable junction box. Your car's wiring harness is full of junctions. The only box I an think of is the fuse box that is made up of two pieces and joined electrically by tiny metal pins subject to corrosion. You have relay boxes for the air conditioner, convertible top if applicable and a big round one sitting on top of your starter motor.

Ninety percent of all electrical issues with old cars are a bad ground. This could be due to missing ground straps, paint on where you are bolting up a cable or sensor, to rust. You will need to either OHM each connection and cable or do what I do and run a twenty five foot long 8 gauge wire to the batteries negative terminal and touch each ground connection with the other end to see if the problem goes away. If it does you know what the problem is and where it is.

Big Dave
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post #4 of 8 (permalink) Old 06-16-2020, 06:01 PM Thread Starter
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Big Dave, thanks for your feedback. The cable junction box is located on radiator support on the passenger side, the ground wire from positive cable side is attached to it. I have attached a couple of pictures to show you location (red arrow)
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post #5 of 8 (permalink) Old 06-16-2020, 06:23 PM Thread Starter
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Thanks, great info site thanks
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post #6 of 8 (permalink) Old 06-16-2020, 08:14 PM
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That is how the factory spliced cables together by puting a ring terminal on one ens and stacking them in the junction with one cable placed every ninety degreees. then all would be bound together by tightening the nut (but not too tight or it will bust out of the plastic it is set in.

Commonly found on police cars only the plastic was red with a hot wire feeding power to the auxiliary running lights (bubble gum machine on top; though with today's LED strobes that reference has lost all relevance), radio, and the siren (once again the old 75 amp meat grinder siren is long gone). the bubble gum machine used to draw 180 amps with four high intensity tungsten bulbs and twelve volt motor to spin it it was the biggest power draw on the car.

Big Dave
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post #7 of 8 (permalink) Old 06-18-2020, 10:00 AM
 
 
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Hi John, that junction is where the alternator wire feeds the battery. It is not called a "ground wire from positive cable" since confusion over the concept of a "ground" can be catastrophic. Follow that wire across the core support and make sure it in good condition all the way to the regulator and alternator. Did you test the alternator? If you have one of the 40amp units, that is not enough. Get you hands on a 60amp one.
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post #8 of 8 (permalink) Old 06-18-2020, 07:30 PM Thread Starter
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Thanks, the wire was frayed. Great insight Thank You
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