The heated seat system warms the seat cushion and the back rest to approximately 37°C (98.6°F) when in the LOW position. The heated seat system warms the seat to 44°C (111.2 F), when in the HIGH position. This system operates only when the ignition switch is in the RUN position.
The system consists of the following components:
| • | The left and the right heated seat switches |
| • | The left and the right heated seat relay module |
| • | The heating elements in the seat cushion and the seat back |
The battery positive voltage (B+) from the trunk compartment fuse block CONSOLE fuse is applied through the switch contacts to the left or the right heated seat module at terminal C and terminal B, when the ignition switch is in the RUN position. This condition may occur with the left and the right heated seat switch placed in either the LOW or the HIGH position.
The relay contacts close in order to apply battery positive voltage (B+) from the trunk compartment fuse block HTD SEAT L fuse, when the battery positive voltage (B+) is applied to the respective heated seat relay module at terminal C. This condition applies also to the HTD SEAT R fuse to the heating elements in the seat cushions.
The heated elements in the seat cushion and the back rest cushion are wired in a series circuit. This circuit is grounded through CKT 850 (BLK) to G302.
Temperature Regulation
The position of the heated seat switch determines the regulated temperature of the seats as follows:
| • | A 200 ohms resistor is in series with the heated seat relay modules LOW/HIGH input at terminal B, if the switch is in the LOW position. |
| • | A 310 ohms resister is in series with the LOW/HIGH input terminal B, when the switch is in the HIGH position. |
| The heated seat relay module differentiates the switch positions by monitoring the voltage drop across the switch. |
A temperature sensor is installed in the seat cushion in order to regulate the temperature of the seats. This sensor is a variable resistor. The resistance changes as the temperature of the seat cushion changes.
The heated seat relay module monitors the sensor resistance through CKT 952 (YEL/BLK) at the sensor input terminal E. The module opens the contacts removing the battery positive voltage (B+) from the heating elements, when the heated seat switch is in the LOW position and the heating element temperature reaches 37°C (98.6°F).
The battery positive voltage (B+) is removed when the heating elements temperature reaches 44°C (111.2°F) with the heated seat is in the HIGH position. In order to maintain the desired temperature, the heated seat relay module cycles ON and OFF.
On Indicator
In order to illuminate the indicator, the battery positive voltage (B+) is applied through the closed switch contacts to the ON indicator LED. This action occurs when the heated seat switch is in either the LOW or the HIGH position. The indicator is grounded through CKT 850 (BLK) at ground G302.
