Some tips IF it is a Vortec 5.0 or 5.7:

97 trucks are not VATS equipped (anti theft)

Turn on the key. The MIL should illuminate. The MIL is the "check engine" light. If it doesnt, that tells us what direction to go.

What kind of scan tool are you using? Connect the scan tool and turn the key on. You should get the VCM data. If not, that tells us a direction to go.

When trying to crank, does the fuel pump run for 2 seconds and then shut off? This is normal.

The 97 Chevy Truck shop manual has a specfic troubleshooting routine on page 6E-557. Usually, it is not the VCM that goes bad. IT can be the ICM.....there is also a specific Ignition troubleshooting sequence suggested.

mike in tucson