'72 interior lighting question

[mr_josh]

Hi all,

Trying to put together the diagrams for my home-brew replacement cab and engine wiring harnesses. I have them nearly done, but I have a couple of little questions. (Keep in mind that I'm 100+ miles from the truck so I can't just go out and look).

First of all, looking at the '72 wiring diagram, there's a wire going to the windshield wiper/washer switch and it takes off from the parking lights circuit. On the diagram, it's an orange-white wire from the windshield wiper switch that connects with the brown parking light wire . I'd be inclined to think that it was an illumination wire, but I would think that would be on the dimmer circuit with the instrument lights. Anyone know what that's about?

Also, do the heater controls have any illumination built in to them?

AND... on this '72 diagram, it says "light switch and horn connector". There is a blue and yellow wire that leads from the light switch connector directly to the horn. And then there is a blue and yellow wire coming from the horn button, in to a fuse, and the other side of the fuse just has an arrow that says "to instrument lights". I assume that these wires are backwards, yes?

Thanks in advance,

Josh

[fordman]

i think that is power in from the two brown wires that connect to it. or it feeds power to the brown wires.

the heat bezel does have a bulb and socket that can be removed from the back of the bezel.so if the socket is there you can hook it up to the harness if it has been unhooked.

that looks like maybe a power wire to or from the instr cluster maybe. i do not know i if would trust the diagrams. thunderfoot has said he has found mistakes in them. they are wired differently than any of the other trucks by that diagram.

[mr_josh]

Yeah, I just looked at it one more time and I see what's happening. The two circuits touch at right angles (making a + sign) and it looks like they cross. I wonder if the '72 diagram is a Chilton manual repro or something. I have been copying and modifying the '72 diagram and double-checking things with the '70 diagram which is just almost the same. I think it's working out. Thanks for clarifying about the light in the heater controls.

As for the wire on the wiper controls, that still gets me. The brown wires should be hot when the headlight switch is pulled to either position, and the wiper switch should be getting its power from the black and white wire going in to the switch. Who knows?

[Thunderfoot]

Good catch on finding the mistakes!

I have found a few mistakes on the diagrams and the 72 horn/instrument lights is one of them, and looks like that wiper one you found is another.
The wiper Orange/white wire should be the power for the wipers it is #763 in the 70 diagram and you see it meets up with #297 which should be a Black/green striped wire...

Below is the diagram that I touched up for the horn and instrument lights...

[mr_josh]

Thanks a bunch, great work.

What app are you using to draw that and -dare I ask- do you have the original file?

[fordman]

i wonder if he is just using ms paint to do that?

[Thunderfoot]

nothing special there... I just used (Microsoft Paint) on the one from the 72 diagrams here to erase and redraw the lines where they should go.

[mr_josh]

LOL, okay, I was hoping you had the original or something. I'm using DesignWorks Lite to do my diagrams, works pretty well for being free.