Wire harness connectors fall into categories based on where they connect—wire-to-wire, wire-to-board, and board-to-board—and whether the environment requires a sealed or unsealed housing.
Picking the right wire harness connector is the difference between a circuit that lasts decades and one that fails mid-drive. These components are grouped primarily by their physical mating style and their environmental sealing level. Nail those two decisions and the rest—pitch, current rating, locking style—falls into place. The table below maps the most common families, while the sections that follow walk through the selection logic.
Wire Harness Connector Categories: The Main Types
The most basic sorting is by connection target. Wire-to-wire connectors join two separate harness sections or repair a cut cable inside a door panel. Wire-to-board connectors attach a harness to a printed circuit board—the dominant style for sensors and control modules. Board-to-board connectors stack or bridge PCBs directly, saving space and eliminating a cable. Splice connectors (butt or inline) permanently join two wire ends for repairs or extensions. Blade/spade quick-disconnect connectors are the automotive and appliance standard for parts that need fast, repeatable removal.
Termination method matters too. A properly crimped connector with the correct tooling outperforms a soldered joint in high-vibration settings, but it requires quality control during assembly. Solder cups and screw terminals suit fixed installations where vibration is low.
Once you know the mating style, looking at a roundup of the best wire harness connectors matched to that type saves time and guesswork.
JST Connector Families: The Most Confused Wire Harness Specs
JST dominates small electronics, 3D printers, and internal sensors. Each sub-series uses a specific pin pitch and current capacity. Using the wrong pitch damages the header or creates intermittent contact. The table below shows the four most common variants.
| Series | Pitch (mm) | Current (A) | Voltage (V) | Common Use |
|---|---|---|---|---|
| JST XH | 2.50 | 3 | – | Battery balance leads, 3D printers |
| JST PH | 2.00 | 2 | 100 | Small electronics, internal sensors |
| JST SH | 1.00 | 1 | 50 | Compact signal connections |
| JST GH | 1.25 | 1 | 50 | Positive-lock latch, compact signal |
Beyond JST, circular connectors with threaded or bayonet locking handle 5A to over 100A and are standard in military, aviation, and heavy-duty equipment. Rectangular terminal blocks suit industrial control panels where multiple circuits terminate in one housing.
Sealed vs. Unsealed: Matching the Connector to the Job
The most frequent mistake is assuming one connector fits every environment. An unsealed nylon 66 housing (roughly IP40) is fine inside a dash or infotainment system. An engine bay oxygen sensor or chassis harness needs a sealed connector (IP68/IP69K) made from glass-filled PBT to survive moisture, corrosion, and constant vibration. Per detailed wire harness assembly guides, the sealing level is the single largest factor in long-term reliability.
High-voltage EV systems add another layer. Battery packs and motor inverters use orange PA66 connectors with a High-Voltage Interlock Loop (HVIL) for safety, rated IP67. ADAS cameras and LiDAR often use shielded metal connectors for high-speed data, combining IP67 with EMI protection. Never use an unsealed connector in a location exposed to road grime, washing, or condensation—the failure won’t show up at the bench, only after months of field use.
FAQs
What is the most common type of wire harness connector?
Blade/spade quick-disconnect terminals are the most widely used in automotive and appliances, valued for fast tool-free removal. For miniature electronics, JST connectors are the dominant standard.
Can I mix JST PH and JST XH connectors in a single harness?
No. The pin pitches differ—2.0mm for PH versus 2.5mm for XH. A PH male pin will not mate correctly with an XH female housing, risking a short or intermittent connection. Always match the series exactly.
What IP rating is required for an engine bay connector?
At least IP67, with IP68 or IP69K preferred for under-hood applications. Unsealed nylon connectors degrade quickly in engine bays due to heat cycles, moisture, and chemical exposure.
References & Sources
- IQS Directory. “Wire Harness Manufacturing Guide.” General classification and selection criteria for wire harness connectors.
- MiniProto. “JST Connector Reference.” Pitch, current, and voltage specifications for JST XH, PH, SH, and GH families.