Chevrolet: 89 Celebrity Tach, ok check, negative terminal

Question
however is does not have a coil since it is a disturbterless ingniton or if it does, i can not find it
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-----Question-----
I just bought an aftermarket tachometer for my 89 Celebrity which has a disutburless ignition with a 2.8L.  I need to find the negative terminal on my coil or it's equivalent.  To my knowledge i have to find a module and plug it directly onto that, any ideas?  Could you help me out please?
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Buba;
   it should have a small -  on the coil. if you hook up the tach and when its running just touch it to the wire you think is the neg. to see if it works do not hook it up just touch it as it will work as soon as you do it , if it dosnt work than  its the oyher wire. ok

Answer
Buba-if it is coil less, than the wire from the dist or module next to it should be the one, did it come w/o the inst.or you can check in the tech. books at the local library if you want to be shure. they will have a photo in the tech books.  ok
check in the book to be 100%