Grand Caravan FWD V6-3.3L VIN 3 Flex Fuel (2002)
Seat Heater Control Module: Description and Operation
Fig.8 RS/RG Heated Seat Modules
Vehicles equipped with heated seats utilize two heated seat modules. The heated seat modules are located under the front seats, where they are secured to
the seat cushion pans. The left heated seat module controls the left heated seat, and the right controls the right. Each heated seat module has three
connector receptacles that allows the module to be connected to all of the required inputs and outputs through the seat wire harness.
The heated seat module is an electronic microprocessor controlled device designed and programmed to use inputs from the ignition switch, heated seat
switch and the heated seat sensor to operate and control the heated seat elements in the front seat and the two heated seat indicator lamp Light-Emitting
Diodes (LEDs) in the heated seat switch.
The heated seat module cannot be repaired. If the heated seat module is damaged or faulty, the entire module must be replaced.
The heated seat module operates on fused battery current received from the ignition switch and integrated power module. The module is grounded at all
times through the seat wire harness. Inputs to the module include a resistor multiplexed heated seat switch request circuit for the heated seat switch and
the heated seat sensor inputs from the seat cushions of each front seat. In response to those inputs the heated seat module controls battery current feeds to
the heated seat elements, and controls the ground for the heated seat switch indicator lamps.
When a heated seat switch request signal is received by the heated seat module, the module energizes the proper indicator lamp (Low or High) in the
switch by grounding the indicator lamp circuit to indicate that the heated seat system is operating. At the same time, the heated seat module energizes the
selected heated seat sensor circuit and the sensor provides the module with an input indicating the surface temperature of the selected seat cushion.
The Low heat set point is about 38 °C (100.4 °F), and the High heat set point is about 42 °C (107.6 °F). If the seat cushion surface temperature input is
below the temperature set point for the selected temperature setting, the heated seat module energizes an N-channel Field Effect Transistor (N-FET)
within the module which energizes the heated seat elements in the selected seat cushion and back. When the sensor input to the module indicates the
correct temperature set point has been achieved, the module de-energizes the N-FET which de-energizes the heated seat elements. The heated seat
module will continue to cycle the N-FET as needed to maintain the selected temperature set point.
