According to the schematic you should have four wires going to the switch, even though it has five terminals.
A red wire for power for B terminal
A black wire ground for the G terminal
An orange wire for accessories for the L terminal
A tan wire for starting for the S terminal
Go to the Toro website I posted, download the service manual with 12 pages. On the bottom of page 9 you will find a picture of how the back of the key switch should look and compare it to yours. Post back what you find.
A red wire for power for B terminal
A black wire ground for the G terminal
An orange wire for accessories for the L terminal
A tan wire for starting for the S terminal
Go to the Toro website I posted, download the service manual with 12 pages. On the bottom of page 9 you will find a picture of how the back of the key switch should look and compare it to yours. Post back what you find.