early model adapter diy.

[stockE30]

i'm looking for a proper diy.
the car is a 84 eta. m50 from a 94 325is.
i have the square connector and a x20 i don't have a pin out so i planned to just splice the wire. can anyone lead me in the right direction.

[stockE30]

bump, also I can do a pin out too. just that is much easier.