The 3-640599-7 is a 7-circuit, single-row MTA-156 receptacle that terminates 18 AWG discrete or ribbon cable via IDC.
MTA-156 Series Position
The 3-640599-7 is the 7-position IDC receptacle in the MTA-156 family. The series covers 2 through 24 positions at the same 0.156" pitch, all sharing the same locking ramp and tin contact finish. The 7-position variant fits a 7-circuit BOM line where a smaller 6-position or larger 8-position would leave an unused pin or require a different housing. The IDC termination is shared across the series, so the same tooling and wire preparation applies.
Wire termination is IDC — no stripping, no crimping. The 18 AWG wire (discrete or ribbon) is pressed into the slot, where the insulation is displaced and the conductor contacts the tin-plated beam. The feed-through feature allows daisy-chaining through the connector, useful for pass-through wiring in a harness.