Heater switch wire positions

[Johnnyb]

So, from a post long ago: https://classicbroncos.com/forums/attachments/dsc01944-jpg.333161/
Power goes to middle and low/high are the side posts?
THX,
JB

 

[DirtDonk]

Correct.
And without a diagram, I believe the red colored wire is low speed (driver-side) and the orange colored wire is high-speed (passenger side).

This sets it up so that the first ON position is high and the second ON position is low.

 

[Johnnyb]

THX, Dirt. Now if only I hadn't forgotten to hook up the resistor before installing the heater box!

 

[DirtDonk]

Oh yeah, that’s what that extra part was!
Not a fun experience after the fact. I wonder if anyone has successfully installed one with the heater box still mounted?
Seems like I remember a few trying over the years, but don’t recall the results.

 

[Lawndart]

This sets it up so that the first ON position is high and the second ON position is low.

I have never liked items that go from -OFF- to -HIGH- then to a lower setting. I swapped my control wires so mine goes from -OFF-LOW-HIGH

 

[DirtDonk]

It seems more natural to do it that way, and that’s how pretty much every other vehicle in the world did it even at the time.
But I always figured it was because Ford knew that these things would take a beating when the motor was exposed to the weather right there above the floor.
Seems like having high come on first would save the trouble of low speed that didn’t work when the motor got old.
Firing up at full voltage to “get the motor running” so to speak.