M-Series Vehicles Wiring Connectors
All American M-Series vehicles have standardized wiring plans based on one set of
circuit numbers and rubberized, waterproof in-line wire connectors that are the same for every vehicle. This makes it possible to use the same lights, switches, trailer
connectors, etc. across the board thus simplifying maintenance, spare parts inventories and tools.
Wiring harness used in M1 Abrams tank. NSN 5995-01-323-5201, "Wiring Harness, Branched".
M-Series Military Vehicles Wiring Connectors
Photo: Courtesy of Rick Crider's Military Light Conversion page.
The wiring is standardized, but there are many exceptions to the standardization. Early M-series vehicles (such as M-37) used the "Douglas connectors" with metal shells, not the rubber shells discussed on this page. Some vehicles use the multi-pin "Cannon connector" (with colored caps in the top photo) for the lights or other components instead of the rubber connectors, and so on. Before doing anything, check carefully the exact situation with your particular vehicle.
Most M-series automotive circuits use AWG 14 gauge wire with black insulation called MIL-C-13486 cable. The part number for the wire is M13486/1-5 in 14 ga. and is readily available from surplus dealers or wire suppliers. You will see the part number
stamped on the wire. A few circuits are 16 ga. (M13486/1-3 or -5) or much heavier for, say, battery to starter. The connectors in the table below are for
14 gauge wire, by far the most common.
In vehicles, all the wiring and connectors are supplied as a branched wiring harness. The harness packages all the circuits for one part of the vehicle into
a bundle with tape wound around to hold it together. Each circuit is identified by a metal band with the circuit number stamped on it.
The circuit terminates with a connector. Female connector pins (male shells) are on the power supply side to minimize potential for shorts. Parts such as composite light assemblies
will have matching wire pigtails with the proper circuit number band on each wire and the mating connector to the harness. A few connection points (e.g., trailer connector, light switch) use a multi-pin "Cannon connector" instead of individual connectors. You may find a circuit terminated with a ring connector, usually for a ground.
The M-series connectors are designed for easy maintenance in the field. The connector pins/sockets are to be crimped onto the cable and can be hand
assembled or disassembled without special tools (special crimpers are available for perfect crimps, but you can use anything). The resulting connection is
solid, stable, and reasonably waterproof. Tool kit to the left (41-K-103-100) includes a supply of connector parts plus the special tools as issued. Photo: Courtesy of Gene Pantano)
The table below gives all the part numbers involved. The connectors are usually purchased as assemblies for either the male or female side. Each side includes
a shell, a washer (male pin side) or sleeve (female socket side), and the connector itself (male pin or female socket). The terminology is a little confusing since the female socket connector is housed in the male shell while the male pin connector is housed in the female shell.
There is a three way adapter (MS27147-1) that is primarily used to add auxiliary equipment (such as radio equipment) to a circuit or to modify a circuit such as when
replacing a generator with an alternator. It has three male pins (female shells) molded into one housing allowing three female connectors (male shells) to mate to it forming
||MS or Part Number
||Terminal Assy., crimped, female
||Shell, male, single (holds female terminal)
||MS27144-1 consisting of items 1,2,3
||Connector, plug, electrical: socket contact, No. 14 AWG,
||Washer, terminal retaining
||Shell, single, female (holds male pin)
||MS27142-2 consisting of items 6,7,8
||Connector, plug, electrical: pin contact, No. 14 AWG,
||Adaptor, connector, 3-way
MS27142 Female shell assembly
(holds male pin)
MS27144 Male shell assembly
(holds female socket)