Only one GEM, I would guess thats its monitoring the power to those components. Heres everything you want to know about the functions.

GEM Controlled Functions
The Generic Electronic Module (GEM) incorporates the functions of several different modules into one and offers diagnostics to easily locate and repair concerns affecting the subsystems that it controls.

The GEM constantly monitors the system and reports concerns in the form of diagnostic trouble codes (DTCs). The DTCs can be retrieved with the Rotunda New Generation Star (NGS) Tester 007-00500 or equivalent through the communication link.

The NGS is a menu-driven tester, allowing the user to run specific diagnostic tests. The NGS can isolate faults in the GEM subsystems through a symptom-driven diagnostic procedure. Connecting the tester to the GEM communication link will NOT alert the GEM. If the GEM is "asleep" when the diagnostic connector is plugged in, the GEM must be "awakened." If the communication link cannot be established, it is advised to turn the ignition to RUN.

NOTE: The GEM has a sleep function to minimize battery consumption. During the sleep mode, the GEM turns off all outputs and monitors only the following:

Door ajar (driver's door, passenger's door, liftgate, rear right and rear left doors)
Key in ignition
Key in RUN or ACCY
Door handles (driver's or passenger's)
Two-step unlock switch
Neutral safety switch
Illuminated entry request — RAP module
If a change of status occurs at one of these inputs while the GEM is asleep, the GEM will "wake up." When the GEM awakens, it performs an internal self test, and begins normal operation. At this point, the GEM will have all of its functions operational.

The GEM will go into the sleep mode immediately after both of the following conditions have been met:

Key in OFF or key not in ignition
After 45 minutes with no change on any wake-up input
The GEM control system has two modes of operation, the normal operating mode and tester dependent diagnostics mode.

The normal operation of the GEM can detect errors. An integral part of the normal GEM operation is the continuous diagnostics capability. Continuous diagnostics detects errors and changes the GEM control strategy. There is no warning light for the GEM; therefore, a DTC concern will direct you to the GEM. Examples of faults that may be detected during normal operation include:

GEM continuous self test (RAM, ROM, EEPROM, A/D checking)
Output driver monitoring (open circuit/short to GND, short to battery)
NOTE: The GEM can only detect open circuit/short to GND faults when the GEM is not energizing a load, and short to battery faults when the GEM is attempting to energize a load.

Illogical combinations of input signals
A description of the subsystems controlled by the GEM follows.

Heated Backlite and Mirror Timer

When the rear window defrost switch is pressed, a 10-minute timer is started and the GEM energizes a relay that provides battery voltage to the heated backlite (and the outside rear view mirrors if installed). The rear window defrost heats up to defog the rear window or melt accumulated snow or ice.

The GEM de-energizes the relay either when 10 minutes have elapsed, the rear window defrost switch is pressed again, or the ignition switch (11572) is turned to OFF or ACCESSORY. The 10-minute timer is temporarily halted if the ignition switch is turned to START and resumes after the ignition switch is returned to RUN.

Windshield Wiper Control and Interval Timer

There are five modes of operation for the front wipers: MIST, INTERVAL (standard and speed-dependent), LOW, HIGH and WASH.

These modes are only active with the ignition switch in the RUN or ACCY position.

Front Windshield Wiper Control (with Speed Dependent Interval Wiper)

Modes: OFF, Interval, LOW, HIGH, and WASH.

The GEM responds to the windshield wiper control commands by interpreting inputs from the steering column seven-position delay/wash and four-position mode select switches. 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 wipers. Delays will automatically adjust at speeds between 16 and 105 km/h (10 and 65 mph).

The GEM relay drivers control three external relays: wiper high/low speed relay, dynamic brake-run relay, and the washer pump relay. When the washer switch is activated longer than 300 ms, the wash and wiper (low speed) functions are provided until the switch is released. The release of the switch will be followed by three low speed wipes. If the switch is pressed between 100 ms and 300 ms (with the mode in the OFF position), the wiper system will provide one wipe at low speed with no wash.

INTERVAL

For standard interval, the time between low-speed wipes will range from 1.5 to 20 seconds. These delays will shorten as vehicle speed increases up to 105 km/h (65 mph).

HI

This is the fastest wiper speed with no dwell. It is selected when the multi-function switch (13K359) is in the HI speed position. If the wash button is pressed for 0.3-10 seconds, the washer pump will energize until the wash button is released.

LO

This is the slowest wiper speed with no dwell. It is selected when the multi-function switch is in the LO speed position. If the wash button is pressed for 0.3-10 seconds, the washer pump will energize until the wash button is released.

WASH

If the wash button is pressed for 0.3-10 seconds, the washer pump will energize until the wash button is released.

Rear Interval Wiper Control

Modes: OFF, Interval, LOW and WASH.

The GEM responds to the rear wiper control commands by interpreting inputs from the rear wiper mode wash switch. There will be two interval wiper settings to provide the following rear wiper dwell times.

Setting Dwell
1 12 Seconds
2 6 Seconds



The GEM relay drivers control two external relays: rear wiper up relay, and rear wiper down relay. When the washer input on the rear wiper mode/wash switch is activated longer than 300 ms, the wash and wiper functions are provided until the switch is released. The release of the switch will be followed by three low speed wipes. In the OFF position, if the switch is pressed between 100 ms and 300 ms, the wiper system will provide one wipe at low speed with no wash.