I have a Gravely ZTX 52 Model 918011. The left control arm control would not engage button to start. When manually pressed machine would start with control arms out. When bringing arms in it would die for the right control arm. We manually held down the buttons with a zip tie and it started. But now when you put the blades in gear it dies. I do not quite understand why? I have trouble with those control arm safety buttons before. How can I fix this problem the right way?