The pins are rectangular

The pins are rectangular
Plug in the pins correctly

The pins and receptacles used in the connectors come in two sizes, The larger of the two is called out as LARGE in the connector drawings. Both the large and small have the same thickness. The large is designed to carry more current.The male pins are normally embedded into the controller header, and the receptacles are held in the connector so that there is not much chance of plugging them in wrong. Unfortunately the MIMA harness uses the pins and receptacles differently, and it is up to you to assemble them correctly.The large pins are no problem as the width to thickness ratio is so large that you can't plug them in rotated by 90 degrees, but the small pins can actually be plugged in 90 degrees from the correct position, which could deflect the stock receptacles spring contact beyond the yield point, and prevent the receptacle from making reliable contact if ever you need to remove the MIMA harness and put the receptacle back into the connector. Please make sure that you insert the pin into the receptacle in the correct orientation. This is why I used clear tubing for the pin insulating sleeves.