On the D4F engine, the
at the back of the engine should have 2 SCART-like plugs entering it from the top.
The left-hand SCART plug should be enclosed by the 'Black Box' - it's a cube roughly 3 inches by 3 inches.
If you can't see it, it's probable that its been removed by the garage/previous owner (although its meant to be Tamper-Proof!).
If so, you probably should be asking why somebody's gone to the hassle of removing it...