On a VG30 the solenoid is part of the starter, it's an assembly. Someone may correct me, but I seem to recall the solenoid terminal has a wire, so it can't be tripped with a screwdriver to test it. However, you can trip the battery terminal to the motor terminal to see if the motor spins. If it does and you're getting a hard click from the solenoid, then either the solenoid ring contact is bad or your engine is seized and preventing the starter from turning. If it's the ring contact or the motor isn't spinning, either way, you replace or rebuild the starter. If you do know for sure the starter is good and the engine isn't seized, then you have a problem upstream like a bad Starter Relay, Ignition Switch, or a bad starter cable.