Expedition 2WD V8-5.4L SOHC VIN L (1997)
General Module: Description and Operation
GEM Circuit Protection
Short Circuit/Battery Voltage
The Generic Electronic Module (GEM) outputs are designed to withstand continuous exposure to a short circuit to ground or battery voltage
without being damaged.
GEM Feature and Functions
The GEM controls the following features:
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Wipers/washers (front/rear).
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Warning chimes.
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Battery saver.
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Illuminated entry and courtesy lamps.
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Driver power window.
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Accessory delay.
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4-wheel drive.
GEM Diagnostics
The Generic Electronic Module (GEM) diagnostics are accessible with the New Generation STAR (NGS) tester and the Service Bay Diagnostic
System (SBDS). The GEM constantly monitors its subsystems for concerns. If a concern is found in one of the subsystems, the GEM will record
the concern in the form of a Diagnostic Trouble Code (DTC).
There are three areas of diagnostic information useful when diagnosing the GEM.
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DTCs - A record of past or present system problems.
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PIDs - the present state of an input or output.
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Active Commands - Gives the ability to turn on GEM outputs without activating the inputs normally associated with the function.
Ignition Switch Positions
The position of the ignition switch is very important to proper Generic Electronic Module (GEM) operation. Often times, erratic or unexpected
operation can be traced to problems on these GEM inputs. The following is a brief description of five ignition switch positions.
Run
When the ignition switch is in this position, battery voltage should be present at the GEM RUN and RUN/ACC input terminals.
Accessory (ACC)
When the ignition switch is in this position, battery voltage should be present at the GEM RUN/ACC input terminal only.
Start
When the ignition switch is in this position, battery voltage should he present at the GEM start/clutch depressed input.
Off and Lock
The GEM does not have an OFF or LOCK Switch State input. The GEM will assume the OFF or LOCK position when there are no RUN,
