I'm looking for a 12V power source _only_ while cranking.

I know that I used one that was I found in my console in my '87 Formula, I wish I could remember what (It might have been something like the P/N switch in the shifter, if it was then this is a 5 speed car which won't have that).

I know that they should all use the same color at the fusebox, what is that color?

 

Same difference

The starter circuit runs through from the Ign switch through either the NSS or the clutch switch to the starter
If you have VATS that circuit also goes through the start enable relay


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What do you mean by same difference?

I have an '87 LB9 TA, doesn't have vats.

Any idea where the start/enable relay is? Almost looks like I can use any wire off of that relay and it should work...

 

A starter enable relay is specific to a car with VATS. Its what VATS uses to disable the starter. Its located in my drivers side kick panel.

What are you working on ?

 

87 TA, LB9 5 speed

After some digging around I found that there is a 3A "Crank" fuse that takes power from the start position on the ignition switch, through the neutral safety switch and then goes to the fuse... I tapped into the back side of the fuse connector with an alligator clip and it worked, so now I'm going to figure out how to get a more permanent connection into that circuit (I hate the simple clip on taps, so I need to find something more appropriate).

I'm still interested in better ideas if you have them

 

CRANK fuse is the best place to get power only when cranking IMO.

If you have the wire feeding the fuse panel already,.... your in luck! ( On your 87; the CRANK fuse might be already in use if you have an in-tank electric fuel pump. ) That fuse box feed wire is factory spliced to the purple wire leading directly to the Starter Solenoid. It only gets power when the key is in "START".