[Moodster]

I'm going to install a separate coil/terminal block to power my aftermarket gauges, headlight harness, etc. However how do I trigger this coil? Do I need to run a wire from the ignition switch or can I use the "I" terminal off the Ford solenoid?

david

 

[JeffTepper]

IIRC the "I" terminal gets 12 volts only when the engine is cranking over. Once the engine has started, the voltage available at the "I" terminal is the reduced voltage (approx 9 volts more or less) that powers the standard ignition coil. If you need a full 12 volts constant run a fused feed from the "+" terminal of the battery, If 12 volts switched, such as for a relay trigger, you will need to tap into the ignition switch for your power.

 

[Moodster]

Thanks for the help, to clarify I need 12 volts switched... so I'll start looking at the wiring diagram for the ignition switch and see if I can find where to tie in.

david

 

[66HertzClone]

It might be best if you picked up the 12 volts directly from the battery or the battery side of the solinoid. Run a heavy gauge wire from there to your block, use a circuit breaker or a suitable sized fuse near the battery. At the fuse block position a relay that is activated when you have the key on. Think about how you will want these connections powered, on when key is in run position only or on when cranking and in run position.

There are many different fuse blocks available for this, take your time and plan carefully.

 

[Moodster]

I think I would want on when in "run position"? I can't imagine I would ever need "on when cranking only" unless I was hooking up a starter.

david

 

[66HertzClone]

I think I would want on when in "run position"? I can't imagine I would ever need "on when cranking only" unless I was hooking up a starter.

david

I should have been clearer, I meant both while running and cranking. Think of having an electric fuel pump for instance.......

 

[Moodster]

Gotcha, an electric fuel pump makes sense.... I guess an electric choke would be another?

david

 

[66HertzClone]

Yes, but for the short cranking time it wouldn't make much of a difference. The power for your gauges might be good to have on while cranking.

 

[Woodchuck]

If you just need a trigger for keyed 12v tap into the heater blower feed wire.

 

[Moodster]

Awesome, thanks Bartl... hadn't thought of that one and I actually know where that wire is!

david