The heated seat system consists of the following components:
• | Heated seat control module |
• | Seat cushion heater element |
• | Seat back heater element |
• | HVAC/CLSTR/BTSI fuse 10A |
Heated Seat Switch
The heated seat switch controls the high and low temperature settings through
a rocker switch that is located near the HVAC control head. Battery positive voltage
is supplied to the switch from the HVAC/CLSTR/BTSI fuse located in the IBCM fuse block.
The heated seat system will operate only with the ignition in the ON position.
Control Module Power and Ground
Battery positive voltage is supplied at all times to the heated seat module
through the battery positive voltage circuit and the HTD SEATS fuse located in the
underhood fuse block. When commanded ON, the heated seat module uses this voltage
to heat the seat heating elements. The heated seat module and the seat heating elements
are grounded through the module ground circuit to G301.
Heated Seat Operation
When the heated seat switch is placed in either the high or low temperature
position, battery positive voltage is applied through the heated seat switch signal
circuit to the heated seat module. At the same time, battery voltage is also applied
through one of two resisters in the switch and the heated seat HI/LO signal
circuit to the module. In response to these switch signals, the heated seat module
closes it's contacts and applies battery positive voltage through the heated seat
element supply voltage to the seat heating elements. When the heated seat switch is
in the HIGH heat position, battery voltage is applied through a 200 ohm resister
and the module sets the seat temperature to high heat. When the heated seat switch
is in the LOW heat position, battery voltage is applied through a 2,850 ohm
resister and the module sets the seat temperature to low heat.
Temperature Regulation
The heated seat system is designed to warm the seat cushion and seat back to
approximately 44°C (111.2°F) when in the high heat mode, or 37°C (98.6°F)
when in the low heat mode. The heated seat module monitors the seat temperature through
the temperature sensor signal circuit and the temperature sensor (thermistor) that
is located in the seat cushion. The temperature sensor is a variable resistor, it's
resistance changes as the temperature of the seat changes. When the temperature sensor
resistance indicates to the heated seat module that the seat cushion has reached the
desired temperature, the module opens its contacts to remove voltage from the heating
elements. The heated seat module will then cycle the contacts open and closed to maintain
the desired temperature.