ORIGINAL: skyblue
I have had problems with APP connectors not making good contact. It seems that ( on assemling the connector) once you slide the metal connector into the plastic housing the connector must lock into the plastic part. If it does not lockin securely the two metal connedtion will make for a poor contact or no contact at all.
It is written in the instructions that you MUST hear a LOUD click when assembling the connectors. If not, the contact is not right and you must pull off the plastic housing and try again. This is not a problem with the connector itself, and installation error can happen with anything - including solder joints.