The heated seats systems consists of 4 heated seats, 2 in the front and 2 in the rear. Each heated seat consists of the following components:

The rear integration module (RIM), driver door module (DDM), left rear door module (LRDM), and right rear door module (RRDM) are also involved in the operation of the heated seats. The system is functional only with the ignition switch in the ON position.

Battery positive voltage is supplied to the front and rear heated seat module through the ignition 3 voltage circuit and the IGN 3 Fuse located in the rear fuse block. This voltage is used to power up the module. Battery positive voltage is also supplied at all times to all four heated seat modules from the following fuses located in the rear fuse block:

This battery voltage is used by the modules to apply voltage to the seat heating elements.

The left and right front heated seat modules are grounded through the module ground circuit and G302. The left and right rear heated seat modules are grounded through the module ground circuit and G301. The left and right front heated seat switches are grounded through the switch ground circuit and G200. The left and right rear heated seat switches are grounded through the switch ground circuit provided by the associated door module.

The heated seat system is designed in order to warm the seat cushion and seat back to approximately 42°C (107.6°F) when in the high position, and 37°C (98.6°F) when in the low position. 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 has reached the desired temperature, the module opens the ground path of the seat heating elements through the heated seat element control circuit. The module will then cycle the element control circuit open and closed in order maintain the desired temperature.

When the heated seat switch is first pressed, the heated seat high/low signal circuit of the heated seat module is momentarily grounded through the HI/LO switch contacts indicating a high heat command. In response to this signal, the heated seat module applies battery positive voltage to the seat cushion/back heating elements setting the temperature level to high heat. When the heated seat switch is pressed a second time, the heated seat high/low signal circuit of the heated seat module is again momentarily grounded through the HI/LO switch contacts indicating a low heat command. In response to this second signal, the heated seat module then sets the temperature level to low heat. When the heated seat switch is pressed a third time, the heated seat high/low signal circuit of the heated seat module is again momentarily grounded through the HI/LO switch contacts indicating a heat off command. In response to this signal, the heated seat module removes battery voltage from the seat heating elements.

When the heated seat is off and the front heated seat switch is pressed once, the heated seat temperature is set to high heat. The heated seat module applies 5 volts through the heated seat high temperature indicator control circuit to the heated seat switch, illuminating the high temperature indicator. When the switch is pressed a second time the heated seat temperature is set to low heat. The heated seat module applies 5 volts through the heated seat low temperature indicator control circuit to the heated seat switch, illuminating the low temperature indicator. After the switch is pressed a third time, the heated seat is turned off, and the front heated seat module removes the voltage from the low temperature indicator.

When the heated seat switch is first pressed, the heated seat switch signal circuit of the rear door module is momentarily grounded through the switch contacts indicating a high heat command. The rear door module then sends a simple buss interface (SBI) message to the DDM indicating the high heat command. The DDM then sends out a class 2 message to the rear integration module (RIM) indicating the high heat command. The RIM momentarily sends a 35 millisecond one shot pulse signal that is pulled low through the heated seat switch signal circuit of the rear heated seat module indicating the high heat command. In response to this signal, the heated seat module will then apply battery positive voltage to the seat cushion/back heating elements setting the temperature level to high heat.

When the switch is pressed a second time, the heated seat switch signal circuit of the rear door module is again momentarily grounded indicating a low heat command. The rear door module then sends out a SBI message to the DDM indicating the low heat command. The DDM then sends out a class 2 message to the RIM indicating the low heat command. The RIM again momentarily sends a 35 millisecond one shot pulse signal that is pulled low through the heated seat switch signal circuit of the heated seat module indicating the low heat command. In response to this signal, the heated seat module then sets the temperature level to low heat.

After the switch is pressed a third time, the heated seat switch signal circuit of the rear door module is again momentarily grounded indicating a heat off command. The rear door module then sends out a SBI message to the DDM indicating the heat off command. The DDM then sends out a class 2 message to the RIM indicating the heat off command. The RIM again momentarily sends a 35 millisecond one shot pulse signal that is pulled low through the heated seat switch signal circuit of the heated seat module indicating the heat off command. In response to this signal, the heated seat module then removes the battery voltage from the seat heating elements turning off the heated seats.

When the heated seat is off and the rear heated seat switch is pressed once, the heated seat temperature is set to high heat. The rear door module applies battery positive voltage through the heated seat high temperature indicator control circuit to the heated seat switch, illuminating the high temperature indicator. When pressed a second time, the heated seat temperature is set to low heat. The rear door module the applies battery positive voltage through the heated seat low temperature indicator control circuit to the heated seat switch, illuminating the low temperature indicator. After the switch is pressed a third time, the heated seat is turned off, and the rear door module removes the battery voltage from the low temperature indicator.

There are 3 levels of load management that are controlled by the dash integration module (DIM). The DIM sends the status of the load management to the rear integration module (RIM) via a class 2 message. The ON/OFF status of the heated seats is reported to the RIM through the status signal circuit of each heated seat module. The RIM inhibits the heated seat function for the heated seats through the heated seat module inhibit signal circuit according to the level of load management. During Load Shed Level 00, the RIM leaves the heated seat inhibit signal circuit open so that each heated seat module is in the normal mode of operation. During load shed level 01, the RIM will cycle the signal from high to low every 0.25 seconds to control the heat level to the low setting. During load shed level 02, The RIM will supply a constant ground through the heated seat module inhibit signal circuit to the heated seat modules. In response to this signal, the heated seat module then removes the battery voltage from the seat heating elements. The instrument cluster will display a BATTERY SAVER ACTIVE message.