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Select Low

The program used by the microprocessor to determine which wheel is beginning to lock up.

Self Test

A computer function that scans systems and subsystems to provide data for troubleshooting.

Self-adjuster

A mechanism on a drum brake that compensates for shoe-lining wear and keeps the shoe adjusted close to the drum.

Self-adjusting Clutch

A mechanism that automatically takes up the slack between the pressure plate and clutch disc.

Self-diagnostics

In automotive computers, especially those for engine control, a program which assesses the condition of the system, including the sensors and the computer itself, and communicates its findings to the technician by means of trouble codes. .

Self-discharge

The discharging of a battery due to chemical action, although there is no electrical demand.

Self-energizing

The placing of brake shoes so that the drum tends to drag the lining around with it, resulting in a wedging action between anchor and drum.

Self-induction

The induction of a voltage in a current-carrying coil of wire, such as an ignition coil.

Self-locking Screw

A screw configured do that it locks itself in place when tightened.

Self-sealing Tire

A tire having a special compound on the inner surface that seals punctures when the puncturing object is removed.

Self-tapping Screw

1. A screw that cuts its own threads without pre-drilling in sheet metal. 2. A screw that cuts its own threads in a predrilled hole in heavy-gauge metal.

Self-Test

A part of the Ford functional Quick Test diagnostic procedure.

SEMA

An abbreviation for Specialty Equipment Market Association.

Semi

Short for semi-tractor or semitrailer.

Semi-independent Rear Suspension

A rear-suspension system in which one rear wheel has a limited amount of movement without affecting the opposite rear wheel.

Semi-tractor

A large truck having a fifth wheel used to tow a semitrailer.

Semiautomatic Welding

Manual welding with equipment that automatically controls one or more of the welding conditions.

Semicentrifugal Clutch

A clutch having weighted components in the pressure plate, such as rollers or release levers, that apply additional force against the pressure plate to hold the disc tighter during high engine rpm.

Semiconductor

A solid material, usually germanium (Ge) or silicon (Si), that integrated circuits are made of, with an electrical conductivity between the high conductivity of metals and the low conductivity of insulators used to control the flow of electricity, containing 4 electrons in its valance shell a semiconductor is nether an insulator nor a conductor.

Semiconductor Ignition System

A term used for electronic-ignition system.