Repairs Problem with John Deere z-turn steering

I have a 6 -7 year old John deer zero turn mower that has worked great for years. The other day the left steering arm stopped working and I have no idea what happened. The right arm still works great but the left one is unresponsive! Any help would be appreciated!!! Help please! I am a recent widow and I am not mechanically inclined but really can't afford a big repair bill. I really need to know if it is a serious problem or if it can be fixed. It is a Z445. Thanks for any help!!!

You are need to have a good look at the connections between the motion arms and the motor,
A sudden stop could very well be the control rod falling off the motor.