1965 & 1966 Ford Truck Wiring Diagrams Notes

Webmaster's Notes: When creating the colorized wiring diagrams for the 1965 and 1966 model years, I compared the two to note any differences between them. I decided to scan them both and then (using Photoshop) layering them over the top of each other for comparison purposes. I found that the two diagrams are absolutely identical. They literally used the 1965 diagram to make the '66 version. All circuits are numbered and colored the same and have the exact same path...with one minor exception.


The main harness circuits going into the connector at the base of the steering column for the turn signal switch are identical...but the two diagrams seem to show a different destination for the circuits up inside the turn signal switch itself, after the connector.

So this made me wonder if this is another Ford engineering SNAFU that got past the proofreader or what, so I started doing some digging in the MPC to see if there was a different switch used between the '65 and '66 models. Here's what I found:

  • C0DZ-13341-A (less mounting plate)
    61-62 F100/250 2WD
  • C2TZ-13341-D
    61-66 F350, 61-65 F100/250 4WD, 66 F250 4WD
  • C3TZ-13341-B
    63-64 F100/250 2WD
  • C9TZ-13341-C
    65 F100/250 2WD, 66 F100 2WD/4WD, 66 F250 2WD, 67-69 F100/350 "Before Ser. G30,001"

As you can see, there were actually four different part numbers used for turn signal switches used in the Slicks era. In a nutshell, the '61-'62 2WDs used one,  all F350 and 4WD up through '66 used another, '61-'64 2WDs used a third one, and the fourth was used on '65-'66 2WDs and '66 4WDs.

So...considering how the original diagrams themselves are labeled, ("F100, F250 6 & 8 Cyl.") and don't show actual application, to me that means essentially that the wiring harnesses themselves between the '65 and '66 trucks are identical, and although the turn signal switches might differ slightly in application, they still connect to the main harness using the same connectors and circuits.

I'm still researching this and will update as more information becomes available.




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