Safety switch failure

[Emare]

I was given a Black and Decker Cordless CMM 1200 24v mower. In spite of the the acid battery weight I love it. To be free of the cord is worth a lot. I was having trouble with the safety key/switch. It wouldn’t make contact. I cleaned up the switch and it worked fine until yesterday when smoke came out of the switch. I took it apart and the contacts were melted. I assumed it was an on off switch so connected the two contacts and tried the main handle/switch. Nothing. Does anyone have a wiring diagram for this machine or some words of wisdom. Thanks for taking time, Mike