RAM 1500 Truck 4WD V8-5.9L VIN Z (2002)
Micro ISO Relay: Description and Operation
Fig. 9 DR ISO Micro Relay
MICRO RELAY
A micro-relay is a conventional International Standards Organization (ISO) micro relay (Fig. 9). Relays conforming to the ISO specifications have
common physical dimensions, current capacities, terminal patterns, and terminal functions. The relay is contained within a small, rectangular,
molded plastic housing and is connected to all of the required inputs and outputs by five integral male spade-type terminals that extend from the
bottom of the relay base.
Relays cannot be adjusted or repaired and, if faulty or damaged, the unit must be replaced.
A micro-relay is an electromechanical switch that uses a low current input from one source to control a high current output to another device. The
movable common feed contact point is held against the fixed normally closed contact point by spring pressure. When the relay coil is energized, an
electromagnetic field is produced by the coil windings. This electromagnetic field draws the movable relay contact point away from the fixed
normally closed contact point, and holds it against the fixed normally open contact point. When the relay coil is de-energized, spring pressure
returns the movable contact point back against the fixed normally closed contact point. A resistor is connected in parallel with the relay coil in the
relay, and helps to dissipate voltage spikes and electromagnetic interference that can be generated as the electromagnetic field of the relay coil
collapses.
