F 250 4WD Super Duty V10-6.8L VIN S (2001)
Multifunction Electronic Control Modules: Description and Operation
Principles of Operation (How Does It Work?)
The following is list of Generic Electronic Module (GEM) controlled functions:
^
4-wheel drive functions
^
front and rear wiper/washer
^
warning chimes
^
keyless entry
^
interior and exterior lamps
^
power windows
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). The ignition switch position is very important to the GEM function. Often times, erratic or unexpected GEM
function can be traced to concerns with ignition switch inputs.
Ignition Switch Positions
The position of the ignition switch is very important to correct GEM operation. The following is a brief description of five ignition switch positions.
When the ignition switch is in the RUN position, battery voltage should be present at the GEM RUN and RUN/ACC input terminals.
When the ignition switch is in the ACC position, battery voltage should be present at the GEM RUN/ACC input terminal only.
When the ignition switch is in the START position, battery voltage should be present at the GEM start/clutch depressed input.
The GEM module 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.
