Brown Power wire to Heater/Fan switch

[VB67bronco]

I can not find the Brown Power wire coming off the electrical wiring harness in my 1967 Bronco. Anyone know how to run a new power wire? Where should the wire start, I want it to end up connecting to the Heater/Fan switch.

https://d1ovggn179d8ws.cloudfront.net/images/products/251/0986(2).JPG

 

[1strodeo]

In my 72 the brown wire goes directly from the Heater fuse to the switch, not sure if 67 is the same though...I have a 66 shop manual if you need something out of it -jeff

 

[1strodeo]

FYI the brown wire is a heavier gauge wire than the majority

 

[bronkenn]

Here is how they were oriented on my 72. The large brown wire comes out wire harness from fuse box to the top terminal of the heater switch.Ken

 

[VB67bronco]

So a Heavy gauge brown wire should be coming out of this fuse box?
http://www.bronco.com/graphics/diagrams/68fusepanel.gif

 

[VB67bronco]

So the Heavy gauge Brown wire just comes straight out of this fuse box??

 

[surfer-b]

If you cant find it run a wire from the back of the ign switch, use the BLK/GR post, to the heater switch, use the heater switch to pwr a "H" and "L" set of relays for the heater fan, this would be better anyway. You will need to place the resistor on the load side, the wire going to the heater fan, of the low speed relay. This setup will take a lot of current out of your main Bronco harness, I do this to my Broncos anyway, the less current through those old harnesses the better.

 

[VB67bronco]

Black/green stripe wire on the ignition switch??

 

[surfer-b]

Black/green stripe wire on the ignition switch??

yes, all it will be used for is to run pwr to the heater switch which will power the relays

 

[VB67bronco]

Thank you very much!!!!!
Im putting in an entirely new Heating system from the hoses to the defrost ducts tmrw.

 

[VB67bronco]

yes, all it will be used for is to run pwr to the heater switch which will power the relays

But the ignition Black/green strip wire runs off 14 AMPs fuse, the Original heater wire comes off a 20 AMP fuse. Can the heater run on the 14 AMP instead of the 20 AMPs it is suppose to run off???

 

[VB67bronco]

Here is how they were oriented on my 72. The large brown wire comes out of the ignition switch to the top terminal of the heater switch.Ken

The ignition switch is the Top left right? The brown wire attaches to the Post in the middle with a ring connector?

 

[DirtDonk]

The Black w/green accessory wire actually FEEDS the fuse (as well as other fuses), rather than run off of it.

The Yellow wire on the ignition switch is direct battery feed from a splice at the largest Black w/yellow charging-loop wire.

So ultimately, in spite of the Brown wire's larger apparent gauge (or at least it's thicker jacket?) it's all fed from the single Yellow wire, through the Black w/green, to the fuse panel and then out to the heater via fuse F1 and the Brown wire.

As mentioned the Brown wire would originally have fed from the fuse panel to the heater switch. So in theory, if you ignore all the other wires for the moment, and simply add a new wire to the back post of the ignition switch and use an inline fuse to protect the circuit, you should be good.

But it also would not hurt to look for anywhere that wire might have been cut off.
Then again, perhaps your Bronco originally came without a heater? Pretty sure it was an option, at least for the early models.
Normally all the wires for all the possible options were still in the harness, but maybe in the early years this was not the case on Broncos? Maybe there just is no wire in yours.

Don't know that though. Someone with more early experience may know.
If you look on the backside of the fuse panel you should see the Black w/green feeding at least a couple of fuses on one buss bar. From the F1 location (should be marked "heater") you should see a Brown wire exiting into the harness.
If not, then yours may have never had it.

Paul

 

[bronkenn]

The ignition switch is the Top left right? The brown wire attaches to the Post in the middle with a ring connector?

Yes it is the top left. I was wrong. The brown wire comes out of the harness from the fuse block and not the ignition switch. Read Paul's post next for clarification.

 

[DirtDonk]

I think there's a slight miscue there Ken. The "Brown" wire on your ignition switch is actually the faded puke-Pink-Brown-ish resistor wire for the ignition coil.
It looks like the same wire as for the heater, but is not.
At least it should not be, but things have been wonky before with Broncos, so it would not be the first time.

But the fact that the wire I think you're referring to is sharing a terminal with the Green w/red wire for the voltage regulator, it has to be the Brown/Pink resistor wire. They are the only ones that share that same post.
In your case yours was one of the years that had two variations on the standard theme. One is an additional Green w/red accessory wire sharing the center stud with the Black w/green accessory feed wire. The second is that the resistor wire runs right up to, and splices directly to the connector with the Green w/red voltage regulator wire.

Some years did not have the additional Green w/red wire, and some years had a Red w/green wire sharing that post, where the resistor wire was connected to it further up near the rest of the harness.
This practice probably started in '72 in fact.

The heater switch's Brown feed wire actually comes from the fuse panel to the heater switch. Like is shown in the fuse panel diagram posted above.
This does not mean VB67 can't do as has been discussed, but that's not where it normally goes from the factory.

Paul

 

[surfer-b]

In the description i gave you the blk/grn wire is only used to for the heater switch to engage the relays, the power source for the heater fan to the relays will come from the Batt side of the starter solenoid, install a 30 amp inline fuse. I figured you understood, I should have made that more clear.

 

[bronkenn]

Thanks for the clarification Paul. I should have went out to the shop and visually checked rather that going by the pics I had. I was assuming that the brown wire was coming from the ignition to the H/L switch and I didn't verify it on the harness. Upon further investigation I see the brown wire does go into the harness and not to the ignition switch. Thanks for the heads up and sorry to the original poster (VB) for the inaccurate info. Ken

 

[VB67bronco]

Thank you for your responses.. but I’m more confused now than before..so, what I’m hearing is
1. Run a wire from the back side of the ignition switch, the post with the black/green wire.
2 Add an in-line 30 amp fuse to this new wire , then attach this wire to top center Spade connector on the Heater/Fan switch.
3. Run the red wire from the Heater/Fan switch to the resistor on the heater box. Run the orange wire from the Heater/Fan switch to the resistor and connect the other orange wire at the end to the orange wire coming off the heater motor..
Correct??

 

[bronkenn]

I believe the wire from the ignition switch energizes the fuse box. The brown wire is ran from the fuse box to the top of the heater switch then to your resistor on the heater box. Paul can explain it better. Ken

 

[DirtDonk]

Well that's the "correct" way Ken, but it sounds like he does not have the Brown wire at all, at least through part of it's normal length. And even though adding a wire to the fuse box like it would have been originally is not impossible, it's certainly more awkward than just adding a new one from one switch to another.
Easier access basically.

So yes VB, in lieu of you finding the original Brown wire (if it's buried in there somewhere) you run a new wire from the center stud/post of the ignition switch to the center blade connector of the heater switch.
I would use a 20a fuse instead of a 30a though, unless you're also planning to swap in a larger more powerful heater motor?

Then the Red wire runs to the resistor, on the opposite side of the resistor from where the motor connects. This is the low speed because the resistor reduces the voltage that the motor sees.
Then the Orange wire to the same side of the resistor as the blower motor. I forget how the jumper system works exactly, but yes, the motor is basically connected directly to Orange for high speed and indirectly (through the resistor) for low speed.

From the factory, the high-speed position is first on the knob. So when you turn the heater fan on, the high comes on first. Then the second click goes down to low speed.

Paul