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Home >> Hummer >> 2008 >> H2 4D Utility Wagon >> Repair and Diagnosis >> External Pages >> Different car >> Section 113 (Seat Heating System & Seat Cooling System) >> Diagnostic Information and Procedures >> DTC B2508 or B2509 (Front Seat) >> Circuit/System Description

Circuit/System Description

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The front seat heating elements are controlled by a common high current relay internal to the Memory Seat Module (MSM) and on the low side by individual element control circuits. Before the MSM will allow heated seat operation, it checks to see if the heating element supply voltage circuits and control circuits are shorted to ground or battery voltage. Once the module verifies that it is not closing into a shorted heating element, it allows heated seat operation. After which it continues to monitor for a shorted circuit.