Purple dash wire identification @ Rear inner wheel well wiring clips

[OX1]

Any idea what this wire is for?
Seems to be coming from ign switch area.

and where can I get the clips that hold
taillight wiring harness to inner fender?

 

[Lawndart]

On the schematic, the only purple one from the ign switch is going to the brake warning switch.

 

[tirewater]

There are clips that hold the tail light harness up? Learn something new everyday, lol. Just the other day I realized there's suppose to be a spring on my tire carrier latch.

 

[OX1]

On the schematic, the only purple one from the ign switch is going to the brake warning switch.

That's the only purple wires I could find on schematic at all.
And those are supposed to be pur-whi. Anyway, I see that connector
in harness under hood, and those wires are much smaller guage than this
wire.

And I don't think it goes to ign switch, it goes into harness right behind switch (just appears to be going towards switch, which I was just using as a reference for location).

There are clips that hold the tail light harness up? Learn something new everyday, lol. Just the other day I realized there's suppose to be a spring on my tire carrier latch.

haha. At one point I pulled them off and at least one was still good.
I do have a 74 body, might have to jack it up out of the mud and see if
those clips are still on it.

 

[House]

The purple wire comes from the ignition switch, through the firewall harness, through the switch, back through the firewall and to the lamp.
It should meet up at the Brake Warning Lamp with a Red/Yellow wire.
Are you sure this isn't the connector OFF of the ignition switch?

 

[DirtDonk]

Look on the side of your ignition switch. If it's got a male blade connector with no wire on it, the Purple one in your hand should be there.
In fact, it probably should be there anyway, whether it's got a stripe or not, because it's got the correct connector for that circuit.

Did your '70 come with a charcoal canister on the frame and a condensing tank behind the driver originally? If it did, then those missing clips were for the metal tubing from the vent lines to the main tank.

I've occasionally seen wires clipped there, but more often than not, on mid-'70 and later models it was for the evap tubing.
Is this for the '70 or are you working on another one? If the '70 what month was yours built in?

Paul

 

[OX1]

The purple wire comes from the ignition switch, through the firewall harness, through the switch, back through the firewall and to the lamp.
It should meet up at the Brake Warning Lamp with a Red/Yellow wire.
Are you sure this isn't the connector OFF of the ignition switch?

Could be, just seemed odd it is such a large wire and darker purple than
the wires going to brake warning lamp connector. I have Stang HB and
was thiking of adapting light to the MC level switch (and may try to
install a switch on the emerg brake pedal mechanism too).

Look on the side of your ignition switch. If it's got a male blade connector with no wire on it, the Purple one in your hand should be there.
In fact, it probably should be there anyway, whether it's got a stripe or not, because it's got the correct connector for that circuit.

Did your '70 come with a charcoal canister on the frame and a condensing tank behind the driver originally? If it did, then those missing clips were for the metal tubing from the vent lines to the main tank.

I've occasionally seen wires clipped there, but more often than not, on mid-'70 and later models it was for the evap tubing.
Is this for the '70 or are you working on another one? If the '70 what month was yours built in?

Paul

Can't see the side, can't see it at all really, so I pulled out my lucky broken mirror, which side am I looking for.

My 70 didn't have any emission stuff on it when I got it,
but it was far from a factory unmolested rig. Not sure what
month. But anyway, are those clips avail, they work really
well for that wiring harness. If not new, I'll start digging
around for used one's.

 

[tirewater]

In the indent of your switch connector you can see the male spade. In your picture it's to the upper left part of the ignition switch connector.

Could be, just seemed odd it is such a large wire and darker purple than
the wires going to brake warning lamp connector. I have Stang HB and
was thiking of adapting light to the MC level switch (and may try to
install a switch on the emerg brake pedal mechanism too).

Can't see the side, can't see it at all really, so I pulled out my lucky broken mirror, which side am I looking for.

My 70 didn't have any emission stuff on it when I got it,
but it was far from a factory unmolested rig. Not sure what
month. But anyway, are those clips avail, they work really
well for that wiring harness. If not new, I'll start digging
around for used one's.

 

[OX1]

In the indent of your switch connector you can see the male spade. In your picture it's to the upper left part of the ignition switch connector.

Ok, duh, plain as day. Thanks for pointing that out.

The other answer is that wire is for the positive side of light and
the connector in engine compartment is for the ground side.
Not sure why the positive side of circuit needed to be so much
larger.

 

[DirtDonk]

The other answer is that wire is for the positive side of light and the connector in engine compartment is for the ground side.

It's a ground plain and simple. Just connect it to the switch, which is the connector's only place to go. It's a ground test circuit at this point.

The other side of the circuit is the 12v power, and both the 2-wire switch on the H-block under the hood AND the tab on the ignition switch are paths to ground.
The plastic switch on the H-block is simply a pass-through when it's open, and when it's closed it grounds to the frame through the H-block.
The ignition switch's connector is called the "proof-out" that many ignition switches had back then. It's just a test-ground, so to speak, that in this case is utilized for the brake warning lamp circuit in a Bronco and other things on other vehicles. Or nothing at all on most other vehicles.

Not sure why the positive side of circuit needed to be so much larger.

I wouldn't worry about it. Kind of over-thinking it when companies like Ford had potentially multiple reasons for making it larger.
Who knows why Ford did it, other than that's just how it worked out.
Maybe they happened to have that color wire in that gauge and wanted to use it up. I don't remember mine being that large (mid-'71), so maybe it was an as-needed or running change kind of thing?
Or a hold-over from earlier models and your under-hood wires already made the transition to the smaller wires, where the under-dash wire changed later?
Or maybe they even felt that under the dash the wire was more prone to damage from being moved around or messed with during maintenance of the dash components, so they made that section larger?
Who knows, but it does not mean anything that pertains to the function of your lamp circuit.

Paul

 

[OX1]

The other side of the circuit is the 12v power, and both the 2-wire switch on the H-block under the hood AND the tab on the ignition switch are paths to ground.
The plastic switch on the H-block is simply a pass-through when it's open, and when it's closed it grounds to the frame through the H-block.
The ignition switch's connector is called the "proof-out" that many ignition switches had back then. It's just a test-ground, so to speak, that in this case is utilized for the brake warning lamp circuit in a Bronco and other things on other vehicles. Or nothing at all on most other vehicles.

I don't have the stock H-block anymore, using the one that
came with hydroboost, since I have 4 wheel disk. Only
thing I could hook the warning light connector to at this point
is level switch in MC reservoir (and that I'd have to run one side
of it back to ground, from what you are saying).

So there is a ground circuit going through the ign switch?
Is that to actuate the light briefly as a check when you first turn on key?

 

[DirtDonk]

Exactly. It's called the "proof out" and that's all it does. Grounds to the dashboard as a test for, in this case, the brake warning lamp.

If you no longer have a pressure differential switch either on an H-block or newer style proportioning valve, there's no need for it.
Make a bracket to hold a plunger switch on your parking brake pedal and use it as a warning light for that.

Paul

 

[OX1]

So I found the one clip (see my first post). Took a couple pics just for reference. If anyone has seen some similar, let me know.