Getting ready to jump into this:





F-6 Electrical X

 

What are those just to the right of each "lighted switch under dash"?

Are the air compressor/vacuum pump/water pump circuits for clutches like on A/C?

I'm surprised those are all electrically controlled. Was that stock way back when?

 

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Full flow ammeters are potential fire hazards. I've seen a lot of old cars and trucks burn harnesses all the way from source to load. More than a few resulted in total vehicle loss. A volt meter or shunt type ammeter is safer.

For the sake of discussion, I see a six volt battery and an alternator. Is the alternator also six volts or the battery actually 12v?

 

The stock Ford ammeters are an inductive ammeter, no power passes thru them. No worries unless the insulation on the wire wears thru.

 

My bad, I forgot to change the battery. The whole system is 12v negative ground, and the red wire passing through the ammeter pickup is going in the correct direction for negative ground. As Ross stated, these ammeters are Hall Effect - no (internal or external) shunt needed, and they only read nominal current anyway. The alternator is 12v 80 amp rated at full load. Thanks for your concern though.
Automotive ammeters of 60 amps or less are internally shunted.

 

It just dawned on me what you were asking. I forgot to label them, sorry. Those are the pressure and vacuum cut in/out switches. It was easier to just rob the symbol than to make up a new one.

 

It's not so much the ammeter itself as the wiring. I realize we're all in the same boat with our trucks but if you're rewiring adding a maxi fuse between the starter and battery cut out relays would be a good idea.

Also, I see an issue at the battery cut-out relay. As it appears you'll lose all power to the truck, except for the under-dash switches, as soon as you have oil pressure. If that's a NO pressure switch you won't have power to the truck or be able to start the engine. I can understand an engine cut off when oil pressure fails but the diagram appears to cut all power, except to your under-dash switches. I don't think you'll want that to happen.

 

Thanks, really appreciate your input.


Correction: The red wire labeled AWG 4 is actually AWG 6, and it fits through the ammeter pickup fine. AWG 4 won't fit.

 

Depending on your turn signal switch, you normally need power at all times to it (incl. engine off) to get emergency flashers. I'm not clear on the point of the cutout either, it seems like the small red is still serving things you'd potentially want dead with engine off. Is the cutout to prevent battery drain during idle periods? How much current can it handle?

 

A maxi fuse could also be placed in the generator to circuit breaker line. Fusible links or underhood electrical centers (read: fuse box) have been used for years to reduce the chance of electrical fire. Vehicles no longer send unprotected power any farther than necessary. It was just a thought since you were rewiring.

And if you're sitting on the side of the road with a dead engine you'll have no lights at all? I mean it's your call, I just wasn't sure if you had intended that.

 

The turn signal circuit (not shown) is powered from the aux fuse panel. Hot at all times.
Small red wire on the cutout relay powers the ignition switch. When the switch is off, no power to anything downstream of it.
The engine has more that 4 psig at idle (at this writing) so that shouldn't happen.
The cutout relay is rated at 100 amps continuous. Cole Hersey. Alternator has the smallest sheave available, so it should put out ~15-20 amps at idle.

 

Interesting. I could put a 75 amp circuit breaker there. Not a big fan of fusible links.
My logic is that if the engine isn't running I don't need lighting, however the turn signals and four-way flashers would be operable.
So far it's ten pounds of wire in a five pound bag since most of this is new circuitry and equipment. COE's really lack good under hood and under dash space.