Battery Isolator switch

[Patrick L.]

Again, find and fix the draw !
If you have problems following the procedure let me know. I'll walk you thru it again.

I still recommend installing the switch where you want to put it.

Installing something in 'series' is just installing it 'in-line'.

[Bruce of MN]

Lots of previous threads on this. Search this forum for "disconnect kill cutoff"

two seaters and four seaters have different good spots for switches inside the cabin.

[katy]

Is the battery installed with a positive ground, as it should be?

Ditto

[aquadave]

Originally Posted by Bill G

Color of the wire is not important. Where the positive side of the battery connects to the frame, unhook and set aside that cable, and place one of the wires from the switch To the battery where the cable was, and connect the other switch wire to the frame. Now the switch is in series. Figuring out where to mount the switch is totally up to you and your preference. The cable you removed and set aside, you can toss it or save it. It is not used with the switch.

Thank you Bill. That's what I was looking for.

[aquadave]

Originally Posted by katy

Ditto

Yes still 6 Volt Positive ground.

[RollinRock]

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Redbird,
Sorry, didn’t post the last pic showing the location in engine compartment under the floor board. Didn’t want to cut the floor board or seat riser.
RollinRock

[rotorwrench]

Basic electricity includes both series and parallel circuits but you really don't need to know everything about the differences unless you are designing a circuit of your own. The model A wiring harness and system is about the most simple set up a person can learn on with exception to say an 8N Ford tractor that even has less circuits. It is simple in the fact that the came with very few electrical components. This is a good link for diagrams.
https://www.mafca.com/downloads/Semi...ex%20Janke.pdf

The lighting system is the most complicated part since it all has to go through that big switch on the front side of the steering box which is kind of a bad place to put a switch but Ford kept it there till 1939. The head lamps have high and low beam circuits. There is a tail light circuit and a stop light circuit plus a park or cowl light circuit. Of all these, the brake light circuit is the most problematic for unknown current draw due to the funky switch that they had for 30 & 31. I'd start with that switch to find the current draw.

It's doubtful that the ignition system would be hot unless the ignition switch is defective. The ElectroLoc switches have been know to have problems after so many years in service.

The horn is not a likely problem area unless the wire inside the horn rod has bad insulation on it.

Most of the later model As have a vacuum wiper if it has a wiper at all and the instrument panel light isn't usually problematic due to it's simplicity but you never know. Most model As didn't have a dome light but they usually aren't problematic unless a rodent got to a wire somewhere.

This brings us back to the big diode in the cut out can for the generator. When you mentioned that it had more draw after it was replaced, that shouldn't be. I don't know what's up with that. I know that poor quality diodes can leak current through but I don't know what diode you have in there. Personally, I prefer the old electromagnetic cut out but a diode should work if it's a good one. It can be checked with a multi-meter on Ohms setting. It will have continuity one way but should have none the other way.

[Ken B]

I would also agree that fixing the problem would be best. I recently worked on a Model A with this disconnect switch. There was so much corrosion/resistance in the contacts that it wouldn't let the full power of the battery to the starter. We bypassed the switch and everything was back to normal. Now the switch is removed.

[rotorwrench]

You have a point there. A switch can be compromised by corrosion even if it originally was rated for the current load of the system. A 20 amp circuit breaker or switch can be used after the starter switch to isolate the battery. The 6-volt system needs the 1 AWG cable for power & ground to insure that the starter will function. A switch on the other side of the starter will still isolate the rest of system and a much smaller switch can be used. The starter likely pulls a lot more amps than anything else in the system. The battery can handle that but it needs those 1 gauge cables to be intact.

[aquadave]

Thank you to all. Installation of switch went well. installed right at my feet, in front of driver's side of seat. Parasitic drain is something to do with the new cutout switch I installed on the generator. will have to get a new one.
I was able to cut two small openings in the floor board for the cables to the switch and the carpet covers these up so all you see is the switch. Fortunately or unfortunately being 6' 5" tall my feet won't hit the cables and wear at them. If my front seat was in the usual position the switch would be under the seat but I had to move the seat back so I could even drive the car.
Again everyone, thank you for your help.

[Patrick L.]

If you're using a standard cutout [ non regulator] then try to get an original. Repo's are junk.