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Ignition Coil Wiring


Jedi Knight
OK. I want to nail this down once and for all.

the coil has two wires going to it.

My "new-ish" Lucas (not the sport) coil is marked "+" and "-"
My old Lucas coil has "SW" and "FB" or some nonsense like that
My Bosch blue coil is marked "15" and "1"

Which wire goes to the dizzy and which one goes to the switch? What does the "SW and "F-something" equate to "+" and "-" ???

I'm assuming that "15" = positive and "1" = negative on the Bosch coil (which is the one hooked up to my car right now) and "15" is the one going to the dizzy and "1" goes to the switch.


Geo Hahn

Country flag
SW = Switch (ignition switch)
CB = Contact Breaker (i.e. the points)

That sytem worked great when everything was positive earth. I think they went to + & - when coils might be used on either polarity.

Think about it... the points cause the coil to fire by interrupting the ground -- therefore the wire to the distributor would be the one marked with the polarity of your ground.

In Bosch-Speak, 15 is 'ignition on power' (positive) and 31 is 'ground' (negative). I don't recall whether your car is still positve ground so I can't say if you got it right.

The good news is that it doesn't make much difference.


Jedi Knight
Thanks Geo.

It's still positive earth so it looks like it is correct.

On another note I installed a pusher fan and stole your idea for 90 degree threaded rod hooks to mount it to the radiator - works like a champ!
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