Liberty Sport 2WD L4-2.4L VIN 1 (2002)
Power Door Lock Relay: Description and Operation
The power door lock system uses the following relays for the front and rear passenger doors only:
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Driver door unlock relay
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Door lock relay
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Passenger Doors unlock relay
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The tailgate uses outputs from the Body Control Module (BCM).
The relays are electromechanical devices that switch battery current to the door lock circuit when the Body Control Module (BCM) grounds the relay
coil. These relays are located in the Junction Block (JB). For complete circuit diagrams, refer to the appropriate wiring information. The wiring
information includes wiring diagrams, proper wire and connector repair procedures, details of wire harness routing and retention, connector pin-out
information and location views for the various wire harness connectors, splices and grounds.
The relays are a International Standards Organization (ISO) micro-relay. Relays conforming to the ISO specifications have common physical
dimensions, current capacities, terminal patterns, and terminal functions. The ISO micro-relay terminal functions are the same as a conventional ISO
relay. However, the ISO micro-relay terminal pattern (or footprint) is different, the current capacity is lower, and the physical dimensions are smaller
than those of the conventional ISO relay
The relay cannot be repaired or adjusted and, if faulty or damaged, it must be replaced.
The ISO relay consists of an electromagnetic coil, a resistor and three (two fixed and one movable) electrical contacts. The movable (common feed)
relay contact is held against one of the fixed contacts (normally closed) by spring pressure. When the electromagnetic coil is energized, it draws the
movable contact away from the normally closed fixed contact, and holds it against the other (normally open) fixed contact.
When the electromagnetic coil is de-energized, spring pressure returns the movable contact to the normally closed position. The resistor is connected in
parallel with the electromagnetic coil in the relay and helps to dissipate voltage spikes that are produced when the coil is de-energized.
