Topic: Convertible top Metal Fuse/Fusible wire

[uapilot]

Hello,
Have a question concerning the power convertible top wiring under the hood of my 1966.
I know there are two different ways Ford pulled power off the battery cable side of the solenoid. One was the Fusible Link wire to a junction mounted on the inner fender wall/battery apron. The other was a metal fuse mounted on the battery cable stud on the solenoid. My Mustang in a San Jose 5/15/66 build and when I got it it had the metal fuse arrangement and I saw no holes in the battery apron indicating it originally had the fusible link arrangement. My question is, which is correct for my car? When did Ford change it from one method to the other?

Thank you kindly, in advance!
David W.

[midlife]

I believe Ford did not utilize fusible links on Mustangs until the 1970 model year.  I think what you are referring to is the circuit breaker.  CB's can be re-set but fusible links are like fuses: once they blow, they must be replaced.

[Bob Gaines]

I believe Ford did not utilize fusible links on Mustangs until the 1970 model year.  I think what you are referring to is the circuit breaker.  CB's can be re-set but fusible links are like fuses: once they blow, they must be replaced.

I don't know about 66 but the many 68 Metuchen and 69 Dearborn convertibles I have worked on all had fusible links. The example is a Shelby with a junction block but the fusible link part of the harness is regular Mustang.

[midlife]

Huh.  You may be right about the convertible power lines attaching to the starter solenoid.  In 13 years of restoring harnesses, I never have never come across one.  I'm pretty sure the 66 era ones had circuit breakers that attached to the battery side of the starter solenoid.
(a little off topic) I have run across some 70 main power feeds that were not fusible links, but most seem to be, which is why I said earlier that 70 seemed to be the year when they showed up on all model Mustangs.

[CharlesTurner]

6F08C322xxx unrestored example...

[J_Speegle]

6F08C322xxx unrestored example...

+1 There are a few other examples visible in the unrestored picture thread section

[uapilot]

Yes Charles,

Thats (in your photo) what I have seen but when I bought my San Jose 66 back in 2017, it had the metal fuse which I am gathering is a Circuit Breaker.  But I have seen many photos of the fusible link wire to the "junction stud" mounted on the inner battery apron.  I was just wondering which was right going forward and heres my reason.

My car is being restored now by Jeff and I am aiming at the most concours I can get with the goal of it falling into the Concours Daily Driver category as I love driving it as often as I can. I am installing a nice sound system that I can remove easily when I go to shows as it is as indiscernible as possible. Speaker boxes on the rear floor, wiring run under console, quick disconnect sound and power, original AM/FM rebuilt to todays standards by Aurora Design, a subwoofer in the trunk mounted in such a way as to remove it without any indications it was there....and my problem is the power coming into the dash area.  I've decided, with Jeffs help, to use the convertible top power cable and tap off of it under the dash to power the amps/speaker boxes & subwoofer. I am concerned about the power draw (amps) and worried I may forget and use the power top while playing tunes to the full capacity and blowing the fuse/CB.  If that happens, rather it not be the fusible link as I have seen photos of them melting and damaging the paint of the battery apron....or so one would think.  I'd rather it be the metal fuse/CB to prevent that possible issue and to have extra CBs incase it does trip.

So with that background I am asking which would be acceptable for my San Jose 66 built on 5/15/1966, fusible link or the metal fuse/CB?

Now I am also wondering, as I didnt know this to be true, if I use the metal fuse/CB....is it truly resettable?  Im looking at one now and I cannot see any clear way to reset it.

Thanks much and thanks for reading my long long story!
Dave

[RoyceP]

The circuit breaker automatically resets after maybe 1 second, or as soon as the short / overload condition does not exist. It's possible to burn one out if you leave power connected and the overload circuit in place long enough.

[uapilot]

I believe Ford did not utilize fusible links on Mustangs until the 1970 model year.  I think what you are referring to is the circuit breaker.  CB's can be re-set but fusible links are like fuses: once they blow, they must be replaced.

So midlife, have one of the "metal fuse/CB" and I cannot see a way to reset it.  I've attached a photo of it.

Let me know....cheers,
Dave

[67gta289]

They are circuit breakers, not metal fuses.  Fuses and fusible links are one shot over-current circuit interrupters.  Circuit breakers are resettable.  These style circuit breakers interrupt due to heat over time which corresponds to current.   The types used here are similar to headlight breakers in that they automatically reset when cooled over time.   I?m not sure what is correct for your situation but can say that the circuit breaker is best.  They also cost more which is why they were used judiciously. 

[67gta289]

Royce, they don?t reset when the cause of the over current condition clears, they reset on time due to cooling.  Cooling occurs because the circuit is broken (interrupted).  If the problem is gone the breaker will remain reset. If not it will interrupt again.  On headlight circuits this is normally described as flashing headlights. 

[Bob Gaines]

Not Charles but I had a couple of ideas that may be applicable to your car. The 60's Ford circuit breakers typically automatically reset when the load is taken off /turned off.  You have used ingenuity to disguise the sound modifications and If your car needs a fusible link like I suspect it does there are things you can do. I would get the very nice repro fusible link that NPD sells (top L pg 231)and use it for a pattern and parts. I could see that with a little effort disassembling the terminals from the wire and pulling the inner fusible wire out and replacing it with a solid wire .You could also just replace the wire given not having the printing on the wire would typically not warrant any kind of deduction in concours driven or trailered as long as the wire itself appears like it should on the outside. You could then hide a circuit breaker on the inside the dash unseen and not have the stress of worrying about a fusible link melting and causing damage .Just some ideas that came to mind.

[RoyceP]

If the cause is still present they keep blowing and never connect the circuit. So for example when the tail lamp circuit is shorted, the result is darkness. If you were to open the trunk and listen carefully without a major freeway next to you you might hear the CB trying to reset - a clicking noise - but it would not fully reset and restore electricity to the circuit until the short is no longer present.

Royce, they don?t reset when the cause of the over current condition clears, they reset on time due to cooling.  Cooling occurs because the circuit is broken (interrupted).  If the problem is gone the breaker will remain reset. If not it will interrupt again.  On headlight circuits this is normally described as flashing headlights.

[uapilot]

Wow, thanks guys!!! 

I like that the CB resets itself...assuming that is the correct setup for my car.  I have this horror story scenario where I drive an hour to a show, upon leaving the show I forget and use the sound system and the top at the same time, blow the fuse and not have a suitable replacement so I am stuck with the top half up for the drive home. I know I could probably disconnect the actuator and manually stow the top...but much rather wait and try again after a cooling period with the sound system off.

Thanks Bob, I know I've seen many 66's at shows with the fusible link but mine had the CB on it and, although I know the inner front apron on the drivers side was damaged in a collision and possibly replaced, I do believe the passenger side battery apron was original and there are were no holes, as I recall, where the fusible link setup would be mounted. I dunno.  BUT, I REALLY like your idea and if Jeff takes me back to the fusible link (because I had Richard put in a NOS battery apron) then I'll definitely use it...and credit you, of course!

All great info everyone!
David

[uapilot]

Side issue,
Has anyone used relays for high draw items such as the headlights so you can limit the amount of juice going through the headlight switch?

I read recently to make sure I use a heavier duty variety vice a lighter duty.  Didnt know they came that way but....
If you did use one, any suggestions on what brand/model to use?  Does it truly matter?

I may use a few relays here and there as the old 66 wasn't envisioned with the more modern higher draw accessories of today.

Thanks much!
David