You can use a voltmeter at the motor terminals to check for voltage, it runs on line voltage.
To run the motor by itself, unplug the stove (for safety) and disconnect the leads to the motor, the attach your cord to the motor. Be very careful, you are working with potentially lethal voltage. If the motor turns, it's okay.
From the maintenance manual:
The Versa Grate System should be running at all times when the stove is turned on. The power is supplied to the versa grate motor through the Purple Wire in the Harness that is connected to a short Purple wire soldered to the backside of the control board.
• Electrical - As an electrical component, the troubleshooting of the Versa Grate Motor can be broken down to a defective gear motor, a defective control board, or issues related to the wiring. The Versa Grate Motor has 2 Black wires. One is connected to the Terminal Block in the back of the stove, making the Common connection. The other is plugged into the Purple wire in the harness. If the motor is not running:
Check to see if there is voltage at the Purple wire in the harness.
If there isn’t any voltage there, check to make sure the Purple wire is soldered properly to the back of the control board and there is voltage at the ¼” Male connector.
If there isn’t any voltage at the control board, the board is bad and needs to be replaced.
Remember: The stove must be turned on when checking for voltage.
If there is voltage at the motor and the motor isn’t running, the motor is bad and needs to be replaced.
Part of the Yearly Maintenance is lubricating the moving parts that make up the Versa Grate system. We recommend using a High Temp Anti-Seize in paste form. This should be applied in the areas indicated in Figures 18 and 19 on Page 39.
[Sorry, the pics didn't come out.]
Fuses:
• The fuses on the control Board. The F1 fuse protects the Auger circuit and the F2 Fuse protects the entire control board. Check these first. (See Figure 2 on page 14 for the location of the fuses on the control board). Replace with 250 Volt, 5 Amp, 5 MM x 20 MM fast acting fuse
So, it appears that there's no separate fuse for the VG motor.