Help - No electrical power at all (67 Barracuda)

[ScreamingFish67]

Ok - I'm adjusting the floats on my carb when (during the process) I turn the car on. It turns on and is running and all of a sudden everything goes dead. I see a fire and am thinking crap the fuel ignited and I'm going to burn my car and house to the ground. Luckily, it was only my fusible link that was on fire. I blew it out and ordered a new one from yearone. Today, I put the new link in and nothing. I mean nothing, no interior lights, radio, headlights or anything.

I used a multimeter tested the battery, replaced the starter relay, have 12.5v going in as well as 12.5v on the line from the battery directly to the starter. I also have 12.5v in/out of the new fusible link. I have power on the other side of the bulkhead and all of my fuses in the fuse block are intact.

I'm not good with electricity, am I supposed to be able to read voltage at the alternator with the car not running? I wasn't getting any volt readings at the "brown" side of the Starter Relay and starter as well as at the alternator. I'm assuming this is normal, all of those spots showed intact "0" when I hit it with the ohmmeter.

Again - I'm just not sure why I have no power to any accessories with a functioning battery? It is an automatic trans, is it possible that a bad neutral safety switch could do this if so where would it be located (console shifter)?

Any thoughts, I am not what you would call electric savvy so please treat me like I no nothing (which is pretty true)!

Thanks All!
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[Dana67Dart]

The fusable link would have only burnt if there was a short. Download the shop manual for yiur year and start tracing the wires from and into the fusable link

 

[67Dart273]

.

It could be the "RED" feedthrough terminal for the fuse link on the road to the ammeter

But you are right about one thing........a fire is never good. Maybe the short was bad enough it burned one of the feedthrough terminals. Only way to find out is to start with a diagram and trace it out.

"The MAD article"

Even if you don't do this mod, this is a great simplified diagram of how the main power distribution works:

Catalog

"Just follow the map" The main power comes from the BATTERY---to STARTER RELAY STUD----THROUGH FUSE LINK---------THROUGH BULKHEAD CONNECTOR------TO AMMETER-------OUT AMMETER ON BLACK------TO WELDED SPLICE

From the splice the thing branches off several ways. The splice is in the black ammeter wire up in the under dash harness. Feeds off to headlights, fuse panel "hot" buss, feeds the ignition switch, and branches off back out through the BULKHEAD CONNECTOR to the alternator

 

[ScreamingFish67]

Thanks - I have tested in and out of the fusable link. It is showing 12.5 volts. Still nothing works though

 

[Tooljunkie]

Something overloaded. I’m suprised fuse link didnt burn up again.
Check your grounds, there was a load on them too. Perhaps one is bad.

 

[ScreamingFish67]

.

It could be the "RED" feedthrough terminal for the fuse link on the road to the ammeter

But you are right about one thing........a fire is never good. Maybe the short was bad enough it burned one of the feedthrough terminals. Only way to find out is to start with a diagram and trace it out.

"The MAD article"

Even if you don't do this mod, this is a great simplified diagram of how the main power distribution works:

Catalog

View attachment 1715193555

"Just follow the map" The main power comes from the BATTERY---to STARTER RELAY STUD----THROUGH FUSE LINK---------THROUGH BULKHEAD CONNECTOR------TO AMMETER-------OUT AMMETER ON BLACK------TO WELDED SPLICE

From the splice the thing branches off several ways. The splice is in the black ammeter wire up in the under dash harness. Feeds off to headlights, fuse panel "hot" buss, feeds the ignition switch, and branches off back out through the BULKHEAD CONNECTOR to the alternator

Thanks for this! - So can I assume that if the ammeter failed that the whole car would go dark? How do I test for power at the alternator if the car isn't running? Do I use the ohmmeter?

 

[Tooljunkie]

Large post on alt to battery positive. Should have continuity

 

[ScreamingFish67]

Large post on alt to battery positive. Should have continuity

Ok at least I did that right.
Thanks

 

[Tooljunkie]

I use a test light to ground too.

 

[Mattax]

Again - I'm just not sure why I have no power to any accessories with a functioning battery? It is an automatic trans, is it possible that a bad neutral safety switch could do this if so where would it be located (console shifter)?

The neutral safety switch would not be the cause. The NSS only completes the grounding circuit for the starter relay.

I'm not good with electricity, am I supposed to be able to read voltage at the alternator with the car not running? I wasn't getting any volt readings at the "brown" side of the Starter Relay and starter as well as at the alternator.

Follow the Battery Positive wire in this '67 Barracuda Charge/start/ignition diagram.
Everything it is connected to will be at Battery Voltage when the engine is not running, and nothing is turned on. Connections are represented as small circles. The Ammeter internally has a metal plate so is the same as a full time connection.
Do you see that the alternator's output (marked Batt) should read battery voltage when the engine is not running and everything is off?
On the Starter relay;
the thinner brown wire (S4) only sees voltage when the ignition switch is position on Start.
the thicker brown wire (S5) only sees voltage when the starter relay is energized by starter switch (yellow wire) and the NSS being closed.

When the engine is running, everything on those wires should be close to the alternator's output voltage.

I used a multimeter tested the battery, replaced the starter relay, have 12.5v going in as well as 12.5v on the line from the battery directly to the starter. I also have 12.5v in/out of the new fusible link. I have power on the other side of the bulkhead and all of my fuses in the fuse block are intact.

Copy the diagram and mark exactly where the voltage is reading 12.5 Voltage
Is there voltage at the alternator output (Batt terminal on the alternator) ?
Maybe its helpful to point out here that Voltage is not power. Voltage only indicates potential to flow, not that there is any. Its like saying there is 70 psi in the water lines of a house. The pressure indicates water will come out of any faucet that is opened. Taking that further, the current is like the gallons per minute flowing, and power is the combination of pressure and flow (volts and amps in electricity). We can think of the the battery like a cistern or water tank on a roof, and the alternator like a well pump.

So can I assume that if the ammeter failed that the whole car would go dark? How do I test for power at the alternator if the car isn't running?

If the ammeter's internal plate (shunt) or connections failed completely, there would be no voltage showing on the other side. If it has a poor connection, it will show as a voltage drop when current is flowing. For current to flow, a connection needs to be completed to ground - for example turning on the headlights.

I'm assuming this is normal, all of those spots showed intact "0" when I hit it with the ohmmeter..... Do I use the ohmmeter?

Use an ohmmeter to measure resistance. Best to do this with the battery disconnected.

The ammeter, when functioning, is also a useful tool. It indicates how much current the battery is providing to run the car (discharging) or whether it is being recharged by the alternator.

The fusible link fails mostly due to a short circuit to ground but can also be caused by repeated cumulative damage. See
Fusible Links in Charging Systems with Ammeter

 

[ScreamingFish67]

The neutral safety switch would not be the cause. The NSS only completes the grounding circuit for the starter relay.


Follow the Battery Positive wire in this '67 Barracuda Charge/start/ignition diagram.
Everything it is connected to will be at Battery Voltage when the engine is not running, and nothing is turned on. Connections are represented as small circles. The Ammeter internally has a metal plate so is the same as a full time connection.
Do you see that the alternator's output (marked Batt) should read battery voltage when the engine is not running and everything is off?
On the Starter relay;
the thinner brown wire (S4) only sees voltage when the ignition switch is position on Start.
the thicker brown wire (S5) only sees voltage when the starter relay is energized by starter switch (yellow wire) and the NSS being closed.

When the engine is running, everything on those wires should be close to the alternator's output voltage.

Copy the diagram and mark exactly where the voltage is reading 12.5 Voltage
Is there voltage at the alternator output (Batt terminal on the alternator) ?
Maybe its helpful to point out here that Voltage is not power. Voltage only indicates potential to flow, not that there is any. Its like saying there is 70 psi in the water lines of a house. The pressure indicates water will come out of any faucet that is opened. Taking that further, the current is like the gallons per minute flowing, and power is the combination of pressure and flow (volts and amps in electricity). We can think of the the battery like a cistern or water tank on a roof, and the alternator like a well pump.
If the ammeter's internal plate (shunt) or connections failed completely, there would be no voltage showing on the other side. If it has a poor connection, it will show as a voltage drop when current is flowing. For current to flow, a connection needs to be completed to ground - for example turning on the headlights.
Use an ohmmeter to measure resistance. Best to do this with the battery disconnected.

The ammeter, when functioning, is also a useful tool. It indicates how much current the battery is providing to run the car (discharging) or whether it is being recharged by the alternator.

The fusible link fails mostly due to a short circuit to ground but can also be caused by repeated cumulative damage. See
Fusible Links in Charging Systems with Ammeter

Ok - First Thank You all for the detailed responses. I feel like I actually have a shot at fixing this. Tonight I tested the alternator looking for voltage and got nothing. I can find it on both sides of the bulkhead before I get to the ammeter but nothing after the ammeter. My thought was to follow the wire up to the ammeter but I don't see how I can do that without removing the dash to get at it. I figure if the ammeter is bad that I would just connect the 2 wires that attach to the ammeter and run like that until I can replace the ammeter with a voltmeter.

Looks like a job for this weekend!

 

[Mattax]

Ok - First Thank You all for the detailed responses. I feel like I actually have a shot at fixing this. Tonight I tested the alternator looking for voltage and got nothing. I can find it on both sides of the bulkhead before I get to the ammeter but nothing after the ammeter. My thought was to follow the wire up to the ammeter but I don't see how I can do that without removing the dash to get at it. I figure if the ammeter is bad that I would just connect the 2 wires that attach to the ammeter and run like that until I can replace the ammeter with a voltmeter.

Looks like a job for this weekend!

You're welcome.
If you can't reach the ammeter (and I don't recall being able to on my barracuda) the easiest check locations are bulkhead connector cavity P and the Starter switch connector hot feed (the cavity with red wire next to the two blue wires).
You can either check for voltage to ground as you've been doing, or disconnect the battery positive and check for resistance between terminals.
It could be the ammeter's connecting studs are not well secured to the metal shunt plate.
Just as likely, more likely in my experience, is a wire terminal connection has failed. This would be one of the metal terminals crimped to the wire.
If any of these have even a strand of wire, or a light connection, it should still indicate battery voltage reading when everything is off. So it seems likely either a wire connection is broken through or is very loose.
To check for a broken or loose wire, disconnect the battery and tug gently on the wires. There also should be signs of overheating by the bad connection.
If the problem is at the ammeter or associated wire terminals, I think its worth loosening the steering column so the instrument panel can be pulled out of the dash enough to see everything.

 

[ScreamingFish67]

Ok - after becoming an acrobat to find and test wires, it appears that the Ammeter is good. The prior owners wiring is interesting. The fusible link goes into "Y" not "Z" on the drawing. I don't think this is an issue. The cabin side bulkhead connector does not have a red wire coming out. In the "y" spot is a blue wire that splits out to a 3 ways. 2 rat tails with female terminals (one which is shows 12.5v). The 3rd gets taped up in this mass of wires that goes up under the dash. Somewhere in the taped up mess a red wire comes out to the ammeter. The red wire is dead but I touched the black ammeter wire to the live blue female off the bulkhead and I have power (the dome light). I've got to assume the wire mess where blue goes to red is the culprit here. Just a thought. If I am ok living without the ammeter can't I just pull the fusible link out of the engine bay bulkhead connector and splice it into the black line running to the alternator? Theoretically, I'd only be cutting out the red wire from bulkhead to ammeter. Is this dangerous? I'm trying to avoid playing around in the taped up wired mess. The accessibility and my skill level are not in my favor here. Also, if I was going to replace the fusible link with a fuse what size would be appropriate?
Many Thanks!

 

[Mattax]

Just a thought. If I am ok living without the ammeter can't I just pull the fusible link out of the engine bay bulkhead connector and splice it into the black line running to the alternator?

Not sure what you're trying to do, but it's best for fusible link to be as close to the battery as possible. Further, its located where it shouldn't catch anything else on fire.
If you replace it with a fuse, its will blow at the slightest over current. Again not sure why you would do that. The battery occassionally is called upon to run the whole car - like when the alternator dies - and with a fusible link it can do that, at least occassionally. It also can occassionally handle the brief high current when recharging after deep discharge. I don't recommend letting it charge at 30 amps for any length of time, but the link gives a little cushion to deal with the situation.

Since the link melted once, I'd say its well worth unwinding that taped mess and seeing what is there. It's not as hard as you think. Where abouts in NJ are you? Something is shorting or high resistance. Are those rat tails loose? Post some pics if you can.
On '67 B, the Y cavity should be a single 18 gage red wire to power the headlights (high beams IIRC). Sorry to say but I think its well worth straightening out the mess.

'67 barracuda bulkhead wire connection

Connector with cavities S through Z removed from firewall.

Inside view with wire terminals removed from cavities S & Z.