So was cranking but then stopped, now nothing, correct?
There is a 20 amp fuse under the helm for the ignition. Verify the B terminal has 12 V.
If good verify the I terminal has 12 V with the key in the run position.
Finally verify the S terminal has 12 V when the key is in the start position.
If all good verify the slave soleniod is getting 12 V to the coil terminal, small one. The other small terminal is ground. Then verify the large terminals have 12V when cranking.
1997 2400 SCR
5.7 Vortec / Bravo 2