Climate Controlled Seat System
PRINCIPLES OF OPERATION - CLIMATE CONTROLLED SEAT SYSTEMClimate Controlled Seat System The climate controlled seat system is able to heat and cool the front seats. Each climate controlled front seat is controlled by a switch located on each of the front doors.
Both the driver and front passenger seat has an independent climate controlled seat system installed. A climate controlled seat module mounted to the bottom of the seat cushion electronically controls the climate controlled seat system. The climate controlled seat system receives power from both the battery power and vehicle run circuits. The vehicle must have ignition ON and the switch set to HEAT or COOL 1, 2, 3, 4 or 5, for the climate controlled seat system to activate. The switch will illuminate to indicate the desired operating mode.
Cabin air is drawn through the seat fan motor and distributed to each of the thermo-electric device (TED) modules located in the seat cushion and backrest. The TEDs then heat or cool the air. The air is then directed into the foam pad B-surface. Channels in the A-surface of the foam pad are used to distribute the air along the surface of the seat. Once the system is activated, the climate controlled seat module uses a set of flexible algorithms to control the heating/cooling modes, and the fan motor speed based on the climate controlled seat switch settings.
The TED uses a "Peltier" circuit of P-type and N-type semiconductors connected in series using copper electrical conductors. The semiconductors are sandwiched between 2 insulating ceramic plates. When current is applied to the TED, one side releases energy as heat, while the opposite side absorbs energy and gets cold. By reversing the current flow, the hot and cold sides reverse.
The temperature differences between the individual HEAT and COOL settings is minimal. For example, it is difficult to distinguish between LOW COOL and MEDIUM COOL settings. Monitoring the seat temperature at different HEAT or COOL settings should not be done as it is ineffective in confirming climate controlled seat system operation.
Heating Characteristics
NOTE: The presence of overtemp faults (DTCs B2729 and B2730) can be induced by incorrect operation of the climate controlled seat system after an initial HEAT setting has been attained. If a HEAT setting is repeatedly turned OFF and ON in an attempt to increase the seat temperature, an overtemp condition can result and the DTC(s) will be set.
- The climate controlled seat system draws approximately 7.5 amps until reaching the set point, and then the system operates at a reduced amperage to maintain the climate setting.
- In HEAT mode, the TED can add up to 40-60°C (72-108°F) to the ambient air temperature entering the system.
- There are 5 manual settings based on the position of the climate controlled seat switch on the center console. Position 1 is the LOW setting and position 5 is the HIGH setting.
- In the LOW setting, the climate controlled seat module is set to maintain TED temperature at 37°C (99°F).
- In the HIGH setting, the climate controlled seat module is set to maintain TED temperature at 65°C (149°F).
- If the temperature at one of the TEDs rises above 90°C (194°F) in the HEAT mode or 70°C (149°F) in the COOL mode for more than 4 seconds, the CCSM will record an overtemp DTC, remove power from the TEDs and go into "Blower Only" mode in an attempt to cool down the TEDs. If the TEDs temperature has not dropped to 85°C (185°F) in the HEAT mode or 65°C (140°F) in the COOL mode after 30 seconds, the CCSM will shut down and remain off until the ignition is cycled. Also if the CCSM detects an overtemp twice during the same ignition cycle, it will also shut down.
- In HEAT mode, there is no linear correlation between the seat fan motor speed and the TED supply voltage. The CCSM will independently vary the fan speed and the TED supply voltage in order to reach and maintain the temperature determined by the switch setting.
Cooling Characteristics
- The climate controlled seat system draws approximately 4.5 amps for the first 12 minutes and will operate at 2 amps thereafter.
- In COOL mode, the TED can remove up to 8°C (14°F) from the ambient air temperature entering the system.
- There are 5 manual settings based on the position of the climate controlled seat switch on the center console. Position 1 is the LOW setting and position 5 is the HIGH setting.
- If the temperature at one of the TEDs falls below 18°C (64°F), the climate controlled seat module will shut down the TEDs. If the temperature continues to drop below 12°C (54°F), the climate controlled seat module will shut down the fan motor.
- In COOL mode, there is a correlation between the seat fan motor speed and the TED supply voltage.
The climate controlled seat system is deactivated by one of the following actions:
- Depressing the momentary HEAT or COOL switch on the center console
- Turning the ignition OFF