You can't hook it to the coil + or the solenoid + because they are the same connection when the car is running. The power for those spots run through the resistor wire. your choke will not get 12v and you will rob power from the ignition.
You have to find a wire that comes from the ignition switch "ON" position that does NOT go to the coil.

 

The "I" terminal bypasses the resistor wire and supplies a full 12v to the coil only in the start position. When the key is released, the voltage at the "I" terminal drops down to the 7-9 volts that is supplied to the coil through the resistor wire. The choke coil needs a full 12v to operate properly, that's why the instructions say not to use the coil for power.

 

Good point ... got me thinking again.

The coil needs a full 12V to quickly energize coil during start up. Coil may have drained during shut down. Need to maximize coil current supply to promote reliable start up. Once car started, current supply to coil is limited through resistor wire to avoid over charging coil.

The "I" post is hard wired to coil "+" terminal and is the source of +12v to the coil "+" terminal only when "S" relay post is energized.

Turning key full CW does not provide +12v to "I" directly. Turning key full CW sends +12V to "S" post. "S" post strokes starter relay and at the same time energizes "I" post w/ +12V. "I" post is connected to coil "+" terminal. Coil "+" terminal gets +12v for as long as "S" post is energized.

When "S" is not energized the coil "+" terminal receives reduced current from resistor wire. The resistor wire is also hard wired to coil "+" terminal from the ignition switch; active when key in run position.

Is that completely correct?

 

That's what I was looking for, thanks.

I guess it doesn't matter to me since I rewired my car and don't even have a resistor wire. Mine is hooked to the coil, I was just wondering if that could have drained my battery or was causing damage. From this explanation, seems they don't want you to do it so you get a full 12v to the choke, but without the resistor, I have a full 12v there.

Got it, thanks again.

 

Since you rewired car w/ resistor at coil.
you may well have full 12 volts at "I" terminal of starter solenoid and of course up stream of coil ballast resistor.

You can connect the choke to the above +12V coil wire provided the wire gauge is sufficient to supply the maximum current requirements of the coil plus the choke. The ignition switch must also be capable of passing this current.

w/o measuring the actual current capacity of this circuit (way over kill) and from a reliability stand point i would just find a less critical circuit to rob current from. do you know the starting load of the choke? Do you know the max current load of the coil?

Other thing you could do is wire choke up stream of coil "+" resistor and verify car runs fine. If it ever gives any trouble all you have to do is unplug choke. choke only drawing current when car is cold. should not wot till car is warm. no big risk to try.

 

if your battery is draining then something is still running w/ key off.
clock will drain batt over time.
coil will drain batt if coil "+" terminal is hot w/ key off.

 

Dang 001mustang you sure can talk a lot about something that is not going to work. Up stream down stream doesn't really matter if you tap that wire it is in parallel and will have the same affect on the coil. I would not recommend tapping that wire wether it has a ballast resistor or not. There are two other places to think about tapping a wire under the hood that are keyed. The neutral safetly switch and the back up lights. If it is a stick shift car the back up light go through the floor board by the shifter so that won't work very well but the neutral safety switch should work fine.

 

The neutral start switch only gets power from the "Start" side of the switch - that won't work. There are wires under the dash for accesories that are controlled by the "ON" side of the switch. These are what need to be used.

 

Either run a 12v wire (16 ga) from the Ign switch "A" terminal to the choke coil or you can also go to the Voltage Regulator's Plug "S" terminal (GRN-Red wire) which has 12V from the Ign switch when on. Stay away from the alternator's stator stud, the I terminal on the Starter relay and the coil+. They are not good sources.

 

the neutral safety switch is a switch installed in wire between ignition switch to starter relay "S" post and is only hot when key is full CW. So I don't know what you are talking about either.

just thought some one might be curious how starter relay works....sorry for trying to help...

btw i recommended against hooking elec choke to coil "+" terminal.