The Ignition Module (outside compartment above power module) provides the 12v DC power to OPEN gas valve, supplies the power to ignition electrode to light main flame AND holds the gas valve open when main flame is sensed.
The ignition electrode is also the flame sensor......if main flame is not sensed then ignition module will remove power from gas valve closing it.
Electrode needs to be directly over burner slots
Gap between electrode and burner should be 1/8" to 3/16"
Electrode must be engulfed by main flame
You can check for continuity of electrode.....
Fridge OFF
Unplug electrode wire at ignition module (check for loose/corroded connection)
One probe of meter on electrode
Other probe of meter on bracket (ground source)
Any readings and electrode is shorting to ground....replace
Here is a service manual that covers your model........
LINK