If the starter does not turn then it could either be bad or not getting power. If a volt meter can not be used to determine that voltage is present, then the starter can be pulled and taken to be tested.
You know the starter is going bad when you have a dragging starter.
Remove the starter and have it bench tested.
There are several things that can keep a Chevy Tahoe from starting including the starter being bad, a dead battery, an alternator, or a fuel pump.
Seized Engine? Flat spot on starter? Bad Starter solenoid? Loose or corroded battery cable? Bad ignition switch? Bad neutral or clutch safety switch?
Remove starter and bench test it for operation and current draw
Sounds like the solenoid on top of the starter is bad. If the plunger return spring is broken, the starter stays engaged all the time.
There can be many reasons why a 1997 Chevy Tahoe will not start after sitting for three days. Reasons include a dead battery, a bad starter, a bad alternator, a loose wire, and no gas.
The control wire to the solenoid may be deteriorated and shorting out. Or, you may have a bad starter.
You need to remove the starter and look at the teeth on both parts.
Remove the battery and take it to an auto parts store for testing. They can tell you if it is bad. If it is good, then remove the starter and do the same thing.
Remove it and have it bench tested.
jump the starter solnoid, if it will crank , turn key on and jump again, if it starts then key switch is ok it would be the starter solnoid that's bad,