General Module: Description and Operation
GEM Circuit ProtectionShort 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:
^ Wipers/washers (front/rear).
^ Warning chimes.
^ Battery saver.
^ Illuminated entry and courtesy lamps.
^ Driver power window.
^ Accessory delay.
^ 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.
^ DTCs - A record of past or present system problems.
^ PIDs - the present state of an input or output.
^ 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, ACC, or START signals present.
Wiper/Washer Control and Interval Timer
Front Wipers
There are four modes of operation for the front wipers: speed dependent interval, slow, fast, and wash. These modes are only active with the ignition switch in the RUN or ACC position. Speed dependent wipers compensate for the extra moisture that accumulates on the windshield at higher speeds. At higher speeds, the speed dependent feature shortens the delay between wipes when using the variable interval wiper feature. Delays will automatically adjust at speeds between 16 and 105 kph (10 and 65 mph).
Rear Wiper
There are two modes of operation for the rear wipers, internal and wash. These modes are only active with the ignition switch in the RUN or ACC positions and both the liftgate and liftgate glass are closed.
Chime Warning
There are five warning chimes and lamps the Generic Electronic Module (GEM) controls: Headlights operating without the ignition ON (chime only), door ajar (chime and lamp), key in the ignition (chime only), driver seat belt warning (chime and lamp), and low washer fluid warning (chime and lamp).
Battery Saver
The battery saver feature removes extended interior lamp power drains from the battery. The Generic Electronic Module (GEM) will keep power available for all interior lights and under hood lamp circuits for 40 minutes after the ignition switch is turned OFF. The battery saver timer is reset by unlocking doors with remote entry key fob, activating a door ajar switch, or changing the ignition to RUN or ACC position. If asleep, the GEM will wake-up when:
^ Any door becomes ajar or is closed.
^ The key is inserted or removed.
^ The ignition switch is turned to ACC or RUN.
^ The doors are unlocked with the remote entry key fob.
Courtesy Lamps/Illuminated Entry
The Generic Electronic Module (GEM) illuminates the interior courtesy lamps when any door is ajar. The GEM also provides illuminated entry when the unlock button is used to unlock the vehicle. All interior courtesy lamps are turned OFF when any of the following occurs:
^ Twenty-five seconds have elapsed since the illuminated entry feature was activated and no door is ajar.
^ The ignition switch is turned to RUN and no door is ajar.
^ Vehicle speed is over 15 mph (a new ajar signal will turn on courtesy lamps only if the vehicle speed is less than 10 mph).
^ A power door lock command is received from the remote entry key fob and no door is ajar.
Running Board Lamps
The GEM illuminates the running board lamps when the interior lamps are activated and the ignition switch is not in the RUN position.
Delayed Accessory (GEM only)
The delayed accessory feature provides power to the power windows for ten minutes after the ignition switch is moved from the RUN to OFF position. If during this ten-minute period either front door is opened, the delayed accessory relay will be de-energized.
One-Touch Window
The power switch for the driver window control has two detents for the down window control. With the ignition switch in RUN or ACC, pressing the first detent (normal mode) allows manual down window control; pressing harder to the second detent (auto) will cause the driver window to automatically move to the full down position. Pressing either the up or down window switch will cancel an auto mode operation in progress.
Transfer Case (Four Wheel Drive-GEM Only)
This vehicle is equipped with Automatic 4-Wheel Drive (A4WD).