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Discussion Starter #1
Would someone "in-the-know" explain the Convertible Top Junction Block for 1966 Mustang Convertible to me, why Ford changed from the 1965 circuit breaker, and then changed back in 1967, how the 66 item works, and how it's supposed to look when installed.

Bryan Cobb
 

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The 1966 Convertible Junction block uses a "fusible link" instead of a circuit breaker.. It was cheaper to manufacture... NPD carries them... They are dirt cheap....I'll post a pic of mine correctly installed..
 

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<a href="http://s270.photobucket.com/albums/jj91/NEFaurora/?action=view&current=P1010017.jpg" target="_blank"><img src="http://i270.photobucket.com/albums/jj91/NEFaurora/P1010017.jpg" border="0" alt="1966 Mustang Convertible Junction Block (Correct)"></a>


Here's what its supposed to look like (pic above) and its correct installation. The installation was copied from an unrestored 1966 Shelby Convertible!! One of the original six cars. This is what yours should look like. Notes: Weirdly designed, The cardboard insulator (in the middle shown mounted on the wall of the inner shock tower) should be folded in the middle (as shown) and installed as shown so that the metal tabs of the junction block are not to make contact with the car body. Go figure.. That's the way it was! Plain, simple, and cheaper than a '65 circuit breaker.. It works just fine. That's the way Ford wanted it.
 

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Discussion Starter #7
It looks like to me, in the picture, that if the top pump stalled in a bind, like one that would trip the 1965 style CB, nothing would happen here except the wires would get hot at the pump would keep running. What is the "FUSIBLE" portion?
 

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It looks like to me, in the picture, that if the top pump stalled in a bind, like one that would trip the 1965 style CB, nothing would happen here except the wires would get hot at the pump would keep running. What is the "FUSIBLE" portion?
The "wire" is the fuse. When overloaded, it dies, like a fuse.
 

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22GT- Humbly disagree. I have never seen the carboard installed any other way on an original 1966 Convertible car. What you provided was a 1967 Convertible top wiring diagram. We are talking 1966 here. Also, If you found or posted a pic of one on an original car, It would at least support your arguement, I also see noting in the above diagram that supports your claim...There isn't any Cardboard mentoned in the above diagram, nor shown, It's just a drawing of the junction. The carboard piece is just an insulator from the body of the car. It does NOT go on the (FRONT) terminal itself.
 

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The "fusible link" when overloaded "Bubbles" or expands, and needs to be replaced if blown... It does not reset nicely like the 1965 Circuit Breaker.
 

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PS: If anyone has any original cardboard installations pictures of a 1966 Convertible junction, Please post them. It would be much appreciated to clear up any arguments. Thanks.
 

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Discussion Starter #13
I honestly don't know! What I DO know is that the threaded post is connected to the hot wire from the battery and I doubt that a Ford engineer in 1966 would leave that HOT 12V post exposed to cause fires.

I also can tell that the 4 spades that cause the phenolic to be raised up 1/4" or so, are isolated from the hot 12V post. I see no reason that a paper insulator would be needed between them and the inner fenderwell except to prevent scratching the paint.

If the short wire, itself, is the FUSE, as y'all seem to indicate, then the JUNCTION BLOCK serves no purpose and the cost of making 70,000+ could have been avoided.
A simple screw and nut could have been used.

I really don't know any more now than I did when I started this thread.

Let's get to the bottom of it, Whataya say?
 

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"What I DO know is that the threaded post is connected to the hot wire from the battery and I doubt that a Ford engineer in 1966 would leave that HOT 12V post exposed to cause fires."

Why not???

The solenoid's posts are not covered.....Why cover the Junction post????????!?!?!?

Think about it...
 

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Coupla comments: The vert power top hook up has been discussed on VMF more than once. Seems like IIRC it's never conclusive!

The so called cardboard is commonly used in electronic/electrcal applications. The oft used engineering technical name is fishpaper!
The fuseable link replaced the circuit breaker for simplicity. Never had one fail and normally simpler is more reliable.

As I recall I got the junction block from MU and NPD that is supposed to be for 68 vert. In each case it was humongous like for a solenoid connection!
 

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I believe the the '67-'70 Junction Blocks were Solid Plastic (either Black or Orange), Weren't they??? The '66 Junction block was its own animal and not like any of the other years.. Now I'll have to do some digging!
 

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FWIW my '68 San Jose convertible had the link shown with remnants of the "fish paper" on the top, covering the connection in the engine bay, not under the base against the apron. No clue if it was OEM but it had been there a long time and a lot of the rest of the car was unrestored and original....:shrug:
 

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.There isn't any Cardboard mentoned in the above diagram, nor shown, It's just a drawing of the junction. The carboard piece is just an insulator from the body of the car. It does NOT go on the (FRONT) terminal itself.
Wanna bet? It's the curved, double-hump-shaped part of the FORD drawing. The phenolic strip is the insulation, putting cardboard between that and the apron accomplishes nothing.

FWIW, Scott Drake, as well as Ford, agrees with me.

 

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Discussion Starter #20
I'll choose 22GT's explanation! The "DRAKE" part photo sold me. We all know that 67's got the circuit breakers, like 65's. The only Ford Wiring Diagram that shows the JUNCTION BLOCK is the 67's. In the diagram, the drawing of the junction block LOOKS exactly like the DRAKE part photo.

THIS ALSO MAKES COMMON SENSE! The two mounting screws, screw into the apron. If either of the power wires' eye hooks rotate on the threaded post and happen to touch either screw, a direct short occurs and you'd probably have a fire.

THE FISHPAPER STRIP MAKES THIS LESS LIKELY TO OCCUR!

Bryan
 
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