I have 95 z28 auto.I can run wire from bat to crank fuse and start right up. I can't get this ro run otherwise. New battery-coil-checked all the links and cleaned all the ground. If it starts from batt to crank fuse don't that eliminate ignition in colum and the switch? Were else can I check or bypass?

 

You're back feeding the system somehow, bypassing the ignition switch. The "CRANK" fuse (3 amp) in the end of dash panel has only one purpose and that is to supply the DERM (Diagnostic Energy Reserve Module) that stores energy to fire the air bags. Has nothing to do with cranking the engine.

When you turn the key to the "START" position, the ignition switch feeds two wires on the ignition switch. The critical one is:

Connector 2 - Pin A - yellow wire feeds - 1) the starter circuit (through the clutch start or or auto trans position switch), 2) the theft deterrent relay (TDR), 3) the DERM

Sounds like the yellow wire or the contact in the ignition switch is not carrying power, but when you apply power to the "CRANK" fuse, you are back feeding the TDR and the starter solenoid circuit. You are bypassing the yellow wire and the ignition switch.

From Shoebox:

http://shbox.com/1/ignswschematic.jpg