Need a little help with the wiring. There are 3 wires that enter through a hole in the rear of the oven. blue, white, and yellow. The yellow is on the igniter. The white and blue are on the top of the gas valve. The white wire jumps from the top of the valve to the bottom of the valve. The other wire on the bottom of the gas valve is on the igniter. How do I check the gas valve?