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Power Issue

tk1218

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Ok, on my 66, the fuseable linkage was fried and I replaced it. I believe it was on wire 37 (it is the wire that does not go to the cluster directly for the ampmeter). I replaced the linkage with a 40 amp fuse and it was working fine.

Last night I was swapping out the cluster with the battery disconnected and turned it all back on when done and the fuse blow. I replaced the fuse and everything worked briefly, but now, no power to anything. The fuse has not blown again.

Looking at the fuse block, it appears there is some custom wiring involved by PO. I will try and get some pics of that tomorrow.

I assume I need to trace the power to the point where it is not working.
 

Viperwolf1

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You have an intermittent short-to-ground under the dash somewhere. I would leave the power off until the problem is found. '66 doesn't have much wiring under the dash. Pull the dash and trace the wires.
 
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tk1218

tk1218

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Ok, had a chance to look at it and here is where I am at. Using Seabsq 66 - 67 diagrams for reference

Issues found and repaired.
Wire 904 was cut at the inside plug and run seperate through the fire wall. Wire had insulation damage. Replaced and runs from ignition to I terminal of regulator.
Wire 38 (black) is run by itself through firewall next to vacuum wiper hole. Wire looked well used so replaced with same gauge wire from Silnoid past cluster. Also, connection after cluster broke when pulled apart, so replaced that also.

Other issues found.

Where wires 297 + 30 join Pic 1, there are also a couple more Black / Green wires that have been cut by PO. Not sure where they go. Also, there is a orange wire that goes to a flasher. The big black and green (297) and wire 30 look ok.

Fuse Block- pic 2- heater fuse only at this time, the rest are not in.
Brown wire cut 2 feet off block - this could be the issue - think it is for the heater. Yellow / black wire not connected to anything, not sure what it is, based on fuse location, might be brake light.

Yellow / black wire pic 3 - wire cut by PO. It goes to same firewall grommet as wire 904. Not sure where it goes.

Where wires - pic 4 - 37, 37A, 25, 37B and 21 come together, there are 2 additional wires not on the diagram. Lt blue cut by PO and Orange / Yellow that terminates to a connector-not connected

Where wire 297 connects to the screw on the ignition, there is a black wire as part of this connection. This wire terminates to a connector and a wire that has been cut. Is this a ground?

All other wires look good and the connections between the firewall and the engine compartment looked ok, just dirty, not burned up.

Sorry so, but any advice would be appreciated.
 

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DirtDonk

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Not helping your current issue, but you might eventually up-size to a 60 amp fuse. If you're running a 55 to 60 amp alternator, you might find yourself blowing a 40 amp fuse now and then even when all is working properly. Since that wire does double-duty as the battery charging wire too.
If you're only running a 45 amp alternator though, you can probably get away with it longer.
And running the smaller fuse now, is probably safer until you track down all the gremlins.

That's a heap of cut wires ain't it?
I'll see if I can add anything constructive to what you've already deduced.

Paul
 

DirtDonk

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Issues found and repaired:

1. Wire 904 was cut at the inside plug and run seperate through the fire wall. Wire had insulation damage. Replaced and runs from ignition to I terminal of regulator.

Should be to the "S" terminal (next to the F with the Orange wire). On an EB nothing goes to the "I" terminal.
Also, #016 (resistor wire under the dash) runs from the same terminal on the switch, out to the ignition coil's positive terminal.


2. Wire 38 (black) is run by itself through firewall next to vacuum wiper hole. Wire looked well used so replaced with same gauge wire from Silnoid past cluster. Also, connection after cluster broke when pulled apart, so replaced that also.

Good. Take extra care with this wire and it's connectors. Everything has to be robust, clean and tight. This wire is literally the heart and soul of your electrical system and powers literally everything on the truck. And re-charges the battery to boot!
It's either Black, or Black w/yellow on the alternator side, and later years was Black w/red up to the starter relay. Would originally had one end running through each of those two large rectangular firewall connectors.

This should also be the one you were talking about with the 40 amp fuse, correct? It's definitely the wire that used to have a fusible link at the starter relay/solenoid, so just confirming with you.

I'll work on the other stuff in another post.

Paul
 

DirtDonk

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Other issues found:

3. Where wires 297 + 30 join Pic 1, there are also a couple more Black / Green wires that have been cut by PO. Not sure where they go. Also, there is a orange wire that goes to a flasher. The big black and green (297) and wire 30 look ok.

The large Green w/black still has the nice ring-terminal on the long center post of the ignition switch then? If so, good. That's most of your accessory power to the cab.
The smaller Black w/green wires (#30) would have gone to power the gauges. It would connect to the input side of the IVR on the back of the cluster. From there the wire with 3 extensions would have gone one each to Fuel, Pressure and Temp gauges.
Ammeter gets the large Black 38 wire through it at the old connector that broke prior to your fix.
The large Black w/green (297A) feeds "keyed-on" accessory power into the fuse panel.


4. Where wire 297 connects to the screw on the ignition, there is a black wire as part of this connection. This wire terminates to a connector and a wire that has been cut. Is this a ground?

Most definitely NOT a ground. Anything connected to the center post of the ignition switch is power distribution only.
I've seen additional wires there before, but it's not in the drawings I have. If it looks factory then, I'm not sure about it. If it's added on by the PO, it could have been to anything.
Bottom line though, is that it's used exclusively to turn something on with the key, in both ON and ACC positions.


5. All other wires look good and the connections between the firewall and the engine compartment looked ok, just dirty, not burned up.

Now that last is a bit of good news. Not sure how they survived the PO's ministrations, but if they look good, that's good.
What about the large Black wires (37 and 38) though? If good, I wonder why they were re-routed through their own separate holes by the PO?

One of life's little mysteries I guess.

Paul
 

Viperwolf1

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Pic 1-One black-green wire there powers fuses #1 and #2. Orange-yellow wire goes to turn flasher from fuse #2.

Pic 2-Heater motor wire is brown coming from fuse #1. Yellow-black wire is for radio.

Pic 3-Figure out which pin it is on the connector.

Pic 4-I don't see those extra wires on any of my diagrams. Might get a pic of the connector.

There are no ground wires on the ignition switch.
 

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tk1218

tk1218

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Paul,

The large Green w/black still has the nice ring-terminal on the long center post of the ignition switch then? If so, good. That's most of your accessory power to the cab. Yes, looks good except for the extra black wire - Pic 5. Also, wire going to I terminal of regulator is on the post.

The smaller Black w/green wires (#30) would have gone to power the gauges. It would connect to the input side of the IVR on the back of the cluster. From there the wire with 3 extensions would have gone one each to Fuel, Pressure and Temp gauges. Yes, it is routed that way

Ammeter gets the large Black 38 wire through it at the old connector that broke prior to your fix. Yes, it is that way

The large Black w/green (297A) feeds "keyed-on" accessory power into the fuse panel. Yes looks good.

Most definitely NOT a ground. Anything connected to the center post of the ignition switch is power distribution only.
I've seen additional wires there before, but it's not in the drawings I have. If it looks factory then, I'm not sure about it. If it's added on by the PO, it could have been to anything. See pic 5, it looks stock to me. I will safely terminate the cut wire on the end.

What about the large Black wires (37 and 38) though? If good, I wonder why they were re-routed through their own separate holes by the PO? Wire 38 appears to have been routed seperate from the factory, has a grommet and everything. Grommet was not in firewall and wire touching firewall (fixed). I replaced the entire wire 38 to the cluster. 37 routes with the main harness through the firewall. I replaced part of 37 by the alt and installed the fuse here.
 

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tk1218

tk1218

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Paul, the 40 amp fuse is on the black and yellow wire between the firewall and the alt. No fuse on the black wire from the battery to the cluster. Could add 1.

As for the regulator, here is how it is wired.

A = Battery side of solenoid, where the power from the battery connects
S = Alt - STA
F = Alt - FLO
I = wire connecting to the post on the ignition
 
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tk1218

tk1218

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New Pictures

VW

See new pictures for #3. Looks like the yellow / black wire goes into the same connection as the cut out green and red wire. It goes to 1 green and red on the other side of the connection.

See new picture for #4, the lt blue wire has been cut and the Orange wire is not connected.

Thanks for your help
 

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DirtDonk

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Paul, the 40 amp fuse is on the black and yellow wire between the firewall and the alt. No fuse on the black wire from the battery to the cluster. Could add 1.

As for the regulator, here is how it is wired.

A = Battery side of solenoid, where the power from the battery connects
S = Alt - STA
F = Alt - FLO
I = wire connecting to the post on the ignition

The original Black wire there at the starter relay would have had a fusible link. Looks just like a nicely molded "blob" of insulation right at the ring. If it's gone, then yes, I would add a fuse.

As far as I know, all early Broncos used the same wiring scheme for the voltage regulator. ONLY F, S, and A are used. There is no wire that should be hooked to the I terminal.
Now, that's not to say it can't work the way you have it, but that wiring scheme is for "idiot light" equipped vehicles only. All Fords with ammeters used F, S, & A only.
F is Orange Field wire to the FLD post on alt. Just like it is now.
S is Green w/red wire switched from the ignition switch.
A is Yellow power that is always on. Same as you have it now.

I don't know if the way you have it now would cause any problems, but it's not correct by the book.

Paul
 

DirtDonk

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I forgot to mention that a local member/friend with a '68 stopped by today and while we were under the hood, I should have looked at the voltage regulator wiring to see if it's the same as yours.

I do think I just learned something new though. I've been basing most of my personal experience with the old harnesses on the '69 and '70 models that I've worked on. In those cases, both of the rectangular firewall connectors had one-each of the large Black charge/power wires running through them.
This '68 though, did not. And it looked factory. And to my memory's eye, the plugs looked physically smaller too.
So the fact that your large Black wires are running through grommets all by themselves may have been a factory thing, on the '66-'68 models.
Hmm, I'm going to have to test that theory. I think I have the remains of the '69's connectors (what was left, after the black wires had a nuclear melt-down) here that I can compare to the '68 the next time I see him.

Can anyone else with a '66 through '68 verify this?
You watching this Gddyap? I'm not sure yours qualifies though, since it '66 doesn't even have a fuse box(!), but you should still have the two firewall connectors. Maybe you can see where your charge wires are routed.

Thanks.
Hey, if this turns out Steve83, it looks like you might still have some more tweaking to do to your next-gen diagrams. Rats! Just when we thought it was in it's last revision!

Paul
 

Viperwolf1

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I'm wondering if this harness was swapped in from an old F100 or something.
 
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tk1218

tk1218

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It does have a fuse block just like my 69 bronco. Maybe the PO swapped this out of a later bronco.

I hooked it back up and the lights are now working. I did not put the dash back on yet because the pink wire off the ignition was getting warm. I disconnected the battery again.

I think the regulator is wired wrong by the PO and I need to review a couple other things. Like the pink wire.

It is funny that it actually was able to run like this.

Of course, this is a early 66 with the eyebrow grill, most things are different on these.
 

Viperwolf1

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Voltage reg. wiring.

Pink wire will get hot with key ON.
 

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DirtDonk

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Yep. Pink wire is the resistor wire to the coil
Resistance = heat.

They usually have a heat-resistant sleeve around them though, for that reason. Yours looks bare. Is that the hot Pink wire you're talking about, there in the image in post #8 with the bullet connector?

Paul
 
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tk1218

tk1218

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Yes, it has a sleeve on part of it. Should I unbundle it from the rest of the wires? Does it terminate on the plus side of the coil?
 
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tk1218

tk1218

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Regulator Wiring

Ok, on the regulator, I need to make the following changes.

* Move the Green/Red wire that starts at the post of the Ignition from the I post of the Regulator to the S post of the regulator

* Run the stator wire off the Alt to the electric choke - I have a 200 in the truck that actually has a electric choke.

Thanks.
 

Viperwolf1

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Ok, on the regulator, I need to make the following changes.

* Move the Green/Red wire that starts at the post of the Ignition from the I post of the Regulator to the S post of the regulator

* Run the stator wire off the Alt to the electric choke - I have a 200 in the truck that actually has a electric choke.

Thanks.

Yes. The regulator was wired for a dash indicator light not an ammeter. That's why I'm thinking the harness was swapped in.
 
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tk1218

tk1218

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Ammeter was not working in the cluster.;) Will see if it works now.

The good news on all of this is that I now have some additional power wires both B+ and ignition switched identified for accessories in the future. I have isolated them into a seperate loom on the harness.
 
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