Author Topic: Alternator harness with a fuseable link?  (Read 2493 times)

Offline turtledriver

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Alternator harness with a fuseable link?
« on: April 15, 2023, 06:28:16 PM »
What's with the alternator harness?  The right one is from my 66 GT.  You see it's got an extra primary wire labeled fuseable link (lower part) with a molded splice that the reproduction lower does not have.  The headlight harness is a little unique too in that it only has one wire that goes to the starter relay as opposed to 2.  The second wire is part of this alternator feed.  Anyone seen this configuration before?  Is there a reproduction of it?

Offline jwc66k

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Re: Alternator harness with a fuseable link?
« Reply #1 on: April 15, 2023, 06:43:34 PM »
The assembly plant, Mustang model and scheduled build date would help.
Jim
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Offline J_Speegle

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Re: Alternator harness with a fuseable link?
« Reply #2 on: April 15, 2023, 06:58:39 PM »
So this is for your 66 GT/289.

In the picture I'm seeing there isn't a left and right example but instead what appears to be a used one of some form on the top and one on the bottom.  Not sure where the "fuseable link" is but is apparent the used upper one is not a factory application for a 65-66

Midlife may recognize the used one but there are a ton of possibilities from allot of different years and applications and allot of things have been swapped and altered over the years.

Here is an original 66 289 alternator wiring and its routing from a late San Jose example



Jeff Speegle

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Offline turtledriver

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Re: Alternator harness with a fuseable link?
« Reply #3 on: April 15, 2023, 07:20:33 PM »
Here's the door tag and a picture of the green lug that connects to the starter relay battery side.

Offline J_Speegle

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Re: Alternator harness with a fuseable link?
« Reply #4 on: April 15, 2023, 07:36:52 PM »
Thanks for the additional pictures showing it was possibly an October 65 build car. Easy to see that this is not factory so what is the intent,  looking at making the old loom work,  restore the car back to the way it was built and or just curious about where this non-factory loom came from?
« Last Edit: April 15, 2023, 11:33:38 PM by J_Speegle »
Jeff Speegle

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Offline turtledriver

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Re: Alternator harness with a fuseable link?
« Reply #5 on: April 15, 2023, 07:48:56 PM »
It's interesting you say this is not factory.  The headlight harness has another clue.  Most headlight harnesses have two wires molded into ring lug to the starter relay.  Here a 66 clearly shows these two wires.  The yellow on goes to the regulator and the black / yellow goes to the fuse box.  On this headlight harness there is only the yellow wire.  Where is the wire to the fuse box?  It's that fusible link thing that goes to the altnator and then the black wire is tied at this lug.  So if this fuseable link is not factory then neither is the headlight harness which I'm struggling to believe as it look very factory.

Offline turtledriver

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Re: Alternator harness with a fuseable link?
« Reply #6 on: April 15, 2023, 09:22:44 PM »
So ultimately what am I trying to do?  The headlight harness is in decent shape and has these plastic "X" pieces where wires break off which repros do not have.  This harness also has the integrated fog lights which also does not seem to exist in the repro world. That's my main motivation in using it..because it believe it to be original.   If it's not original what could it have possibly come from?  I could just replace all the wires and have it work but I think what I have is factory.  Without the alternator harness and fuse link primary wire the headlight harness doesn't work because it's missing the black / yellow wire to the relay.  Does anyone have a 66 GT with the integrated fog lights?  What does the wire to the starter relay look like?

Offline carlite65

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Re: Alternator harness with a fuseable link?
« Reply #7 on: April 15, 2023, 09:36:46 PM »
you keep using the term 'fusible link'. please show us a pic of just what you are referring to.
5F09C331248

Offline turtledriver

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Re: Alternator harness with a fuseable link?
« Reply #8 on: April 15, 2023, 10:31:26 PM »
Yes on the molded end that connects to the starter relay battery side it says fuse link.   I have to assume that means it's a fusible link.  This would be where all the current for lights, accy etc plus charging for the alternator back to the battery

Offline J_Speegle

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Re: Alternator harness with a fuseable link?
« Reply #9 on: April 15, 2023, 11:29:54 PM »
So ultimately what am I trying to do?  The headlight harness is in decent shape and has these plastic "X" pieces where wires break off which repros do not have.  This harness also has the integrated fog lights which also does not seem to exist in the repro world. That's my main motivation in using it..because it believe it to be original.   If it's not original what could it have possibly come from? 

Not sure if you have compared the wiring to one of the wiring diagrams.  As you can see they don't always agree with one another or are 100%. Sometimes that have, for lack of a better term for the time period, cut and paste errors from earlier years




You will notice this one indicates the plugs/junctions also





.............................. Does anyone have a 66 GT with the integrated fog lights?  What does the wire to the starter relay look like?

Here are a few from unrestored 66 GTs. No fusable link or indicator in any. Have no picture of any loom or wire at the starter relay/solenoid that looks anything like the one in your picture





Jeff Speegle

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Offline turtledriver

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Re: Alternator harness with a fuseable link?
« Reply #10 on: April 16, 2023, 12:15:57 AM »
It's super puzzling.  I'm missing the wire in yellow.  I'm pretty sure this is part of the headlight harness and it wasn't cut... it never existed.  On most every other car it was molded in the same ring terminal with the yellow wire.  I only have the yellow wire.  Instead of the ring lug with 2 wires I have the fuseable link wire in red as part of the alternator feed.  So the headlight harness cannot work without the red lead.  It's like they are matched pair.   I've never seen another like this.  I acquired this last year.  It had been sitting in a garage untouched since 1976. It was pretty original and complete.  Still had bias ply tires on it.  I cannot bleieve the headlight harness is not factory. Only the mustang used this harness... no falcons or cougers etc. 

Offline midlife

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Re: Alternator harness with a fuseable link?
« Reply #11 on: April 16, 2023, 01:22:42 AM »
Fusible links began to show up in 1971 alternator harnesses; for sure by 1973.  The first fusible link in main harness wiring was in 1970.  I've seen some 1969 headlight harnesses with fusible links, but those are not typical (probably service replacements). 

What the original poster has is certainly not correct for 1966.
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Offline turtledriver

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Re: Alternator harness with a fuseable link?
« Reply #12 on: April 16, 2023, 11:00:39 AM »
I'm not as familiar with a 1971 harness.  Could the headlight harness of a 1971 fit perfectly in a 1966 with no modifications or changes, along with the integrated fog lights?  Connects up to the under dash harness too?
 This post is almost as much about the missing black /yellow wire from the headlight harness as it is about the fuseable link in the alternator harness.  My alternator harness also has the yellow jumper to the engine harness which is typically part of the headlight harness.  My alternator harness is a little beat up and was looking to replace it.  The headlight harness is in good shape but will not work without this odd alternator harness.  If it did not originally come on this 1966 where did it come from?

Offline aaatp

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Re: Alternator harness with a fuseable link?
« Reply #13 on: April 16, 2023, 11:21:21 AM »
Was the fog light wiring, only integrated with the headlight harness, in 1965, and non integrated in 1966?

Offline midlife

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Re: Alternator harness with a fuseable link?
« Reply #14 on: April 16, 2023, 12:12:11 PM »
Was the fog light wiring, only integrated with the headlight harness, in 1965, and non integrated in 1966?
Both 65 and 66 foglamp wiring was integrated with the headlight harness; in 1967, it was separate.
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