I recall having used a connector family from Amp (now TE) that is very similar to the Molex Mini-Fit Jr family. These connectors are NOT interchangeable. The Amp connector has round pins, the Mini-Fit Jr connector has square pins. However, the body styling is very similar, both in size and polarization keying.
I've been searching but can't seem to find that family. Can anyone tell me the family name or typical part number?