Ignition switch on my 30

Lefthander1930

Lefthander1930

Senior Member
I bought this 30 coupe and some of the wire I don't understand. With my trouble light I have power 24-7. I'm looking to hookup a gauge that works when you start the car. Is there a point or place to hookup that on when the key is ? Does the ignition switch have a Acc terminal ?
 
If it is the original ignition switch (popout) there is no ignition on acc terminal, it is wired between the coil and distributor
 
The original wiring path is terminal box to coil( hot all the time), other side of coil to ignition switch, other side of ignition switch to distributor.
Probably how the replacement switch is wired but when the car was modified from original ignition switch it hard to say what was done.
If the wiring is changed—- terminal box to ignition switch, ignition switch to coil, other side of coil to distributor then you can have switched power from ignition switch.
 
I personally do not recommend attaching accessories to the ignition circuit. The reason being that if an accessory electrically malfunctions intermittently or completely it could also affect the ignition circuit. As indicated, the switch you are using is a basic single pole on-off which is the type I have in my A. I would use a simple single throw multiple pole toggle or rotary switch to power accessories. I have an accessory toggle light switch hidden behind the left side of the dash panel.
 
Technically, a circuit is only hot when the switch is on to complete the current path. The original Electro-Lock ignition switch breaks the circuit between the coil + terminal and the distributor so it controls the ground path to the breaker points. The breaker points control the coil function to get high tension induction for ignition which requires a timed opening sequence to get the pulsating DC current to make the coil induct that high tension voltage.

Modern ignition systems control the power side of the coil instead of the ground side. All of the pre-war and some post war Fords have a limited ignition switch function. When Ford started to use electric gauges for instrumentation, the ignition switch only controlled the ignition circuit and the instruments. Prior to that, the switch only controlled the ignition. Lighting and other electrical features had their own switches and fuses after Ford finally started using circuit protection.

Just to ADD, the original Ford ignition switches had a very low current carrying capability. I also don't recommend adding more loads to those early type switches. New circuits should have their own switches and circuit protection.
 
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