Ice maker wire arm won't stay up/off

The ice bin in our freezer is overflowing. Noticed wire signal arm was down. Tried to move it into locked "up" or OFF position, but it would not stay up. Removed bin, checked for any ice build up, stuck ice cubes – none found. Arm movement doesn’t seem restricted. Just seems like arm is not "catching" or locking in up position. Any suggestions on how to fix?