1986 fc3s non turbo s4 13b

The car was originaly running. I took the uim off to do the injectors and put it all back together and it'll crank and crank and crank but won't fire over. I went back through and made sure all of my grounds were connected but while I was looking around I found this plug hanging. I don't remember ever unplugging it and can't seek to find where it goes. Hopefully this is the reason it won't start. Any help would be appreciated. Its a 2 prong female connector and its green with a black stripe.and it comes from the same wore bundle harness that the only electrical plug going to the throttle body comes from

 

There's a temp switch on top of the water pump housing on some turbos and autos. The other models would have the wiring in their harness but no sensor to connect it to. It's not your problem.

 

have you checked the connection at the AFM?