Hi Tom and
to the forum.
The following diagram clearly shows the two sets of four wires you are asking about which should be exactly the same as the ones on your Magic Pie Edge harness:
The four core cable on the motor harness is for pedelec
(PAS) and reverse functions, whereas the four core cable on the control harness supplies battery voltage to a suitable LED headlamp and horn via the light switch on the throttle unit and the horn button on the cruise/horn switch unit respectively.
The GM pedelec sensor usually has Red, Black and Green wires which connect to the Red, Black and Yellow wires on the motor harness:
Red to Red
Black to Black
Green to Yellow
If you wish to utilise the reverse function
(which may be handy on a trike) you will need to wire a simple On/Off switch to the Black and Blue wires on the motor harness. Switching the Black and Blue wires together will activate the reverse function if it is enabled in the software. The maximum reverse speed can be set independently of the maximum forward speed so that it will go much slower in reverse.
Alan