1970 with SM465.....backup switch?

[Facetime]

So I re-wired the blazer with a painless kit. I was of course not thinking when I threw the old harness away. I am trying to reconnect the back-up lights and am stumbling. The harness has two wires that are supposed to connect to the back up switch on the tranny. The only switch I can locate is a single post switch that looks like a temp probe. Any one have any input or thoughts? All of the replacement switches I can find look nothing like what I have here. Thanks in advance for those that can help. Cheers!!