'57 F-100 Ignition Switch

mike42

mike42

Well-known member
Morning Guys.....

I've replaced my Holley 4-Barrel and there is an electric choke wire that has to be hooked to the ignition switch.

There are 4 four posts on the switch. Which one do I wire it to ?

ST
BATT
IGN
ACC

It's -7º here right now and don't want to be working out there too long. Want to get it correct the first time.

Many thx.....Mike
 
IMO ONLY!

If wiring to IGN SW, you will want the lead on the RUN terminal. No resistor and do not attach on IGN circuit to coil as it may interfere with the ignition system of the engine.

A better way would be to run a relay straight from BAT or ALT S (stator) as the amperage to the CHOKE may overload the IGN SW.

What did instruction sheet say?

:eek:

The circuit should also be fused... ;)
 
The instructions are confusing that’s why I asked the question. If I run a fuse........which terminal as noted above ?

Thx
 
mike42 said:
The instructions are confusing that’s why I asked the question. If I run a fuse........which terminal as noted above ?
Thx
Click to expand...

If you run a new wire for the choke heater it should connect to the IGN or 'C' (coil) terminal on the ignition key switch.

ST = start position of the key switch, powers the starter solenoid.
BATT = battery power to the key switch.
IGN = power to the ignition coil, thru the ballast resistor
ACC = provides power to the accessories without powering the ignition circuit

With any luck there is a Red with green stripe wire from the Ign/Run terminal of the ignition switch to the Ballast Resistor (wiring diagram link & 2 ballast resistor examples below).
There is also a black wire from the other terminal on the ballast resistor to the '+'/ign terminal of the ignition coil. Don't connect the choke heater wire to these terminals.

You should be able to connect the choke heater wire to the same terminal on the ballast resistor as the red/green wire from the Ign switch. This will power the choke heater any time the ignition is on. The choke heater is fairly small and shouldn't draw too much power for the red/green wire.
Or connect another wire to the 'Ign' position on the key switch and run it to the choke heater. A fuse in that new wire where it connects to the Ign switch is a very good idea.

http://www.oldcarmanualproject.com/tOCMP/wiring/5765wiring%20diagrams/Ford/MWire5765-195.jpg

I like a few after-market things on my old car as much as anybody else (elect choke, stereo, driving lights) but... 'Keep it Simple' is a valid approach too. The less parts you add, the less things you have to create other problems in the future.
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dmsfrr.....

The ignition switch is in an ungodly area of the dash and hard to get to. Is there anything in the engine compartment that I could run the wire to without hooking up to the switch. I bought a 10 amp fuse and wire and would use that to hook up.

Thx....Mike
 
mike42 said:
dmsfrr.....
The ignition switch is in an ungodly area of the dash and hard to get to. Is there anything in the engine compartment that I could run the wire to without hooking up to the switch. I bought a 10 amp fuse and wire and would use that to hook up.
Thx....Mike
Click to expand...
Mike,
from post #4...
"You should be able to connect the choke heater wire to the same terminal on the ballast resistor as the red/green wire from the Ign switch. This will power the choke heater any time the ignition is on. The choke heater is fairly small and shouldn't draw too much power for the red/green wire."

10 amp is too big to do any good, a smaller fuse should be fine for the choke element. I suspect it's 1 or 2 amps at most(?).
Is your ballast resistor and/or ignition coil mounted just above the engine on the firewall, or on the intake manifold?

I haven't hooked mine up yet but IF the new wire from the ballast resistor to the choke isn't more than a foot long, I'd personally be inclined to not use a fuse at all.

Dennis

.
 
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KULTULZ said:


IMO ONLY!

If wiring to IGN SW, you will want the lead on the RUN terminal. No resistor and do not attach on IGN circuit to coil as it may interfere with the ignition system of the engine.

A better way would be to run a relay straight from BAT or ALT S (stator) as the combined amperage draw to both IGN and CHOKE may overload the IGN SW (statement correction)..

What did instruction sheet say?

:eek:

The circuit should also be fused... ;)
Click to expand...

ALT?! On a '57?

I need to check how many orbits I make without having to return to Earth...
icon_frown.gif
 
Guys....this is not a stock '57 F-100. It's running a Mustang 5.0L bored and stroked to Coyote Specs with 5-Speed and 3:56 Rear Gear. Alternator and Electronic system. So the truck may look stock....but, I can assure you it is not ! There is more engine than truck for an old man !! LOL

There is no resistor at all mounted. The instructions show running the choke wire to ignition switch with fuse, but as I said....it is almost impossible to get to in that part of the dash. I would have to take out the seat and parking brake lever and a brace under the dash. Not a pleasant task to say the least.

So with all that said....if I run a wire from the choke through a smaller amp fuse....where would I attach the wire in the engine compartment without going through all the gymnastics of trying to hook up to Ign Switch ?

Thx.....Mike
 
mike42 said:
Guys....this is not a stock '57 F-100. It's running a Mustang 5.0L bored and stroked to Coyote Specs with 5-Speed and 3:56 Rear Gear. Alternator and Electronic system. So the truck may look stock....but, I can assure you it is not ! There is more engine than truck for an old man !! LOL

There is no resistor at all mounted. The instructions show running the choke wire to ignition switch with fuse, but as I said....it is almost impossible to get to in that part of the dash. I would have to take out the seat and parking brake lever and a brace under the dash. Not a pleasant task to say the least.

So with all that said....if I run a wire from the choke through a smaller amp fuse....where would I attach the wire in the engine compartment without going through all the gymnastics of trying to hook up to Ign Switch ?

Thx.....Mike
Click to expand...

:confused:

Makes a big difference...

Not knowing exactly what setup you have and it's being a late IGN System with an EEC processor I guess...

The only safe way I know is to power the choke circuit directly off the ALTERNATOR.

Below is an easy setup diagram.

classy-inspiration-edelbrock-electric-choke-wiring-diagram-diagrams.jpg


This method is factory style for your period drive train.

DO NOT source power from the IGN SW! You want the power source isolated from the electronics.
 
mike42 said:
Guys....this is not a stock '57 F-100. It's running a Mustang 5.0L bored and stroked to Coyote Specs with 5-Speed and 3:56 Rear Gear. Alternator and Electronic system. .....
Thx.....Mike
Click to expand...
All late model under the hood, but not worth mentioning earlier :confused:
You could have had a real answer about 2 weeks sooner.
 
We had 42º's the last couple days so I wired up the choke to stator post on alternator. Works just fine except I need to get the idle rpm down a bit. It was at 1,600 rpm, but the instruction sheet said it was factory set to that. I'll figure out that adjustment when weather stays warmer !

Thx

Mike
 
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