Well I am sorry I frustrated you. I wanted this thread to be all about SCRs and not MOSFETS as the previous one was.
Then why not state that in the original thread?
I also included a schematic which I hope can help.
You should've done that in the first place; always include a schematic if possible.
Anyways... you stated that SCRs are difficult to switch off. This is acceptable because I only need the switch from 1-2 to 2-3 to happen once. Is their now a way anyone knows that can do this?
Do you understand that: one you turn an SCR on, it will remain on until the power is interrupted?
Suppose you have 2 to 1 connected and you want to disconnect 2 to 1 and connect 2 to 3. The problem is, in order to disconnect 2 and 1, you need to disconnect the power to the whole circuit.
This is why we suggested MOSFETs because all you need to do is remove the gate signal and they turn off.
It doesn't matter how many threads you start or even if you ask the same question on another forum, the answer will be the same.
There's other important information you've missed:
If the switch going to be on the positive or negative side of the supply?
What signal are you using to switch it?
Then there' the information that you posted in the other thread which people responding to this one might have not read:
The voltage is 13V and current is 3.5A.