Commander 4WD V8-4.7L VIN N (2006)
Relay Box: Description and Operation
Junction Block
An electrical Junction Block (JB) is concealed beneath the driver side of the instrument panel in the passenger compartment of the vehicle. The JB is
accessed by pulling down on the steering column opening cover (2) exposing the lower steering column and portions of the instrument panel wiring
harness. The JB combines the functions previously provided by a separate fuse-block module and relay center. The JB serves to simplify and centralize
numerous electrical components, as well as to distribute electrical current to many of the accessory systems in the vehicle. It also eliminates the need for
numerous splice connections. The JB houses blade-type mini fuses, blade-type automatic resetting circuit breakers and International Standards
Organization (ISO) relays.
The molded plastic JB housing is secured with four screws and two snap retainers to the JB mounting bracket behind the instrument panel steering
column opening cover (3). The steering column opening cover can be pulled downward to disengage the latches and provide service access to all of the
fuses, relays and wire harness connectors (1) of the JB.
The JB contains six relays that are integral to the housing assembly. The relays cannot be replaced separately. If any of the relays are diagnosed
inoperative or damaged the complete JB unit must be replaced. The six relays are:
-
Lock relay
-
Unlock relay
-
Driver door unlock relay
-
Rear wiper relay
-
Ignition "RUN" relay
-
Ignition "RUN/ACCESSORY DELAY" relay
The JB unit cannot be repaired and is only serviced as an assembly. If any internal circuit or the JB housing is inoperative or damaged, the entire JB unit
must be replaced.
