BBQ070 help

[Unkle Bread]

I have an old BBQ070. Let my kids use it and found the temperature probe wires hanging down. I looked at the controls and cannot see where they were connected. There is a set of prongs in the upper right hand corner that’s seems to be missing a plug.
Anyone know where I can find out what I am missing and is it possible to upgrade the controls? This unit does not have a digital dIsplay