Topic: wiring harness question

[DWhitaker]

I am working on a 68 fastback and have a total front to back wiring harness from Scott Drake. In stringing out the taillight harness, I find no provision to plug in the gas tank sending unit or the crossover wire for the right side quarter interior light. Am I missing some sub assemblies that does not come with the harness? This car was disassembled by someone else and it is entirely possible some pieces are missing. Thanks for any help or suggestions.

[ruppstang]

Those are not in the 68 tail light harness. It is a seperate one that runs down the RH side of the body.
Marty

[DWhitaker]

Marty,
  Thanks for your quick reply. That is exactly what I needed to know. Guess I'll have to check and see if that wiring is available from Drake. I appreciate your help and knowledge.

[midlife]

And a bit of trivia: only for the 1968 Mustang does the fuel line runs down the right side;  all other Mustangs from 64.5 through 73 are part of the tail-light harness.

[DWhitaker]

Midlife,
  I was not aware  of that at all. Kinda weird they would do that for one year only. Ford must have decided that was not a better idea after only one year.

[midlife]

After seeing all of the 64.-5 through 73 wiring harnesses and all of the changes, I believe there were some real idiots designing things.

In 71-73, the tach version headlight harnesses had wiring for the ammeters.  The main lead to the battery side of the solenoid had a fusible link, the first time Mustangs used them for the main harness.  However, because of the ammeter wiring, there was another #10 gauge main power lead going to a junction box that also tied into the battery side of the starter solenoid.  So...if you had a massive short somewhere, you could still pull power through this junction box while blowing the fusible link at the same time.  It makes no sense whatsoever. 

The 1970 main harness is the only year that contains the main power lead that goes all the way to the starter solenoid. 

Another bad idea was the 67/68 use of the foot pedal activation of the wipers/washers.  I'm surprised it lasted two years.

In 1966, there were three different variations of the constant voltage regulator, each with their own distinct plug on the main harness.

Oh well, stuff like this keeps me busy...

[DWhitaker]

Midlife,
  I got the new subharness that runs down the right side rocker panel for the 68. It only has 2 wires in it, one for the fastback courtesy light and one for the fuel sending unit. It dead ends at the sending unit. On the old harness, it has 3 extra wires going in and does not dead end at fuel sender, but has one 2 prong plug and 2 other separate wires that appear to plug into something in the rear. Any ideas what these 3 extra wires go to?They appear to be original as they are inside the fish net protector.  It does not show this harness in the Osborn assembly manual. Thanks for any help.

[midlife]

Midlife,
  I got the new subharness that runs down the right side rocker panel for the 68. It only has 2 wires in it, one for the fastback courtesy light and one for the fuel sending unit. It dead ends at the sending unit. On the old harness, it has 3 extra wires going in and does not dead end at fuel sender, but has one 2 prong plug and 2 other separate wires that appear to plug into something in the rear. Any ideas what these 3 extra wires go to?They appear to be original as they are inside the fish net protector.  It does not show this harness in the Osborn assembly manual. Thanks for any help.

There was a very rare option for a low fuel sensor, which requires two separate lines to the fuel tank in addition to the courtesy light.  I've seen 3 of these so far.  Could the extra lines be for the radio reverb (another very rare option)?  Where this connects to the main harness, what sort of plugs are there?  Also, what are the extra wires' insulation color?  Usually, the color can give a great clue as to their function.

[TLea]

Trunk light

[DWhitaker]

There was a very rare option for a low fuel sensor, which requires two separate lines to the fuel tank in addition to the courtesy light.  I've seen 3 of these so far.  Could the extra lines be for the radio reverb (another very rare option)?  Where this connects to the main harness, what sort of plugs are there?  Also, what are the extra wires' insulation color?  Usually, the color can give a great clue as to their function.

OK, have the harness in hand now and will try to give a better description. On the front where it goes into the underdash harness, there is a 2 prong plug(both male fittings, one yellow and one black wire), one male plug(red plug end, green with yellow stripe wire), one male plug(yellow plug end, black wire), one female plug(white plastic end, light green wire).  On down where it goes through the quarter is the wires with blue plug end for courtesy light, a red plug end with 2 green wires that appears unused. Then a little farther back, a larger black wire with black female plug end, and a 3 prong female red plug end(and single green with yellow stripe wire). At this point, it has been kinda butchered but it ends with a 2 prong plug(1 male, 1 female) and 1 female plug end with white plastic end as on the one at the front. I think both you and TLea may be right about the possibilities that some of these may be just unused provisions for options the car did not have. Car was not equipped with low fuel sensor, reverb or trunk light. Thanks very much for all help. I certainly appreciate it.

[midlife]

For 1968, the two prong yellow/black wires should be yellow/white and black/blue (fuel and courtesy lights, respectively).  The low fuel line is green/white, not to be confused with the front turn signal line.  There's a interconnect harness between this portion of the rear tail-light harness and the convenience lamps, one of which was low fuel.

I have yet to see a 68 Cougar, but have seen 67's, 69's, and 70's.

I still think this might be a low fuel line system...maybe from a 68 Cougar that was installed by a PO?

[DWhitaker]

Thanks Midlife. It is a definite possibility the wiring has been changed since it is so butchered there at the back. The new harness will supply what I need since car has none of these other options, I was just curious why the repop harness was not made exactly like the original. Guess it's a good thing I don't need any of those other wires.