190 key switch replacement

 I have a broken blade on the back of my switch. Could tell something wasn't right and luckily got it in the shop before all connection was lost. It is a 5 blade switch with only 3 wires to it now. I can see that at sometime there was a 4th but I need to find it. The 5th blade is empty.   It looks like an Indak switch on the key anyway but no numbers on it. Any recommendations on a tractor supply / orscheln  type switch I can try to find? It seems to be a 3 position switch 

 Thank you 

2  bat 

1  ST 

2 IGN 

The switch illustration in the book is showing nothing going to the S terminal. It also shows the white and the red w white stripe going to the I terminal. Red going to the B terminal. The old switch is not labeled but it has 3 wires. None of them went to the same terminal. 

 I can understand the solid red because it also runs to the ammeter. I know my old one did not have the white and the red w white on the same terminal. Also the old switch had 5 terminals but none of them were tied together like this new switch. It has 5 but since 2 are doubles it is only 3 posts.  Any ideas on what I should do? Sorry to be pain but don't want to burn the switch up.

Thank you  

Thank you 

It's pretty scary the type of components the vendor(s) that built these wiring systems used for wire size and the Ignition switches. They put Garden Tractor Ignition switches in these big Tractors to keep the cost down and to get the Purchase order to make the harnesses for these Tractor companies. It wasn't just AC. All of em' did that. Anything that's mass produced $ add up when building the unit.  That's why you see so many cobbled up wiring harnesses in Tractors over the years. The components as well as the gauge wire were borderline at best for the loads run through them and components failed due to high resistance which makes heat, and eventually wire, components, & plugs burned up stopping the Tractor dead in its tracks, and also possibly starting a fire behind the dash area. Seems like the only ones that made it this long with an original system in it had low hours on the machine. The work horses had harnesses replaced and systems cobbled to keep em' in service.  That's why it took me so long to get a good OEM system to use as a pattern to build my new systems on some models of these Tractors. The other no,no that these vendors did was pile up wires on one terminal. In the electrical world we call that "stacking". Worst thing you could do to a switch that isn't rated for the current that flowed through it. It was only a matter of time and "POOF" up it went in smoke! A four bladed switch would have 10-11 wires to it instead of using a higher rated amperage switch with multiple blades to handle the load. Oh well, that's the way it was back then I guess....

Steve@B&B