Silverado 2500 4WD V8-6.6L DSL Turbo (2010)
Seat Heater: Testing and Inspection
Heated Seat Inoperative (Factory Installed, KA1)
Heated Seat Inoperative (Factory Installed, KA1)
Diagnostic Instructions
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Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
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Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
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Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure Instructions)
provides an overview of each diagnostic category.
Circuit/System Description
The driver and front passenger heated seats are controlled by separate heated seat switches located on the door panels. When a heated seat switch is
pressed, ground is momentarily applied through the switch contacts and the switch signal circuit to the door lock/window switch. In response to this
signal, the door lock/window switch sends a serial message to the memory seat module (MSM) indicating the heat seat request. The MSM then applied
battery voltage to the seat cushion and seat back heater elements through a common voltage supply circuit. Each individual heater element is grounded
by the module through separate low side drive control circuits. The heater element control circuits are pulse width modulated (PWM) to ground by the
module in order to control the seat temperatures by regulating the current flow through the heater elements. The MSM relies on 4 independent inputs
from temperature sensors (thermistors) located in the seat back and seat cushion of the driver and passenger seats. The temperature sensor resistance
varies based on the temperature of the heating element causing the signal circuit voltage to change. Once the seat reaches the switch set temperature, the
MSM will then cycle the control circuits of the heating elements ON and OFF in order to maintain the desired seat temperature based on the feedback
voltage from the sensors. The MSM then monitors the current flow through the heating elements and the of rate change of the temperature sensor to
verify correct heated seat operation.
Reference Information
Schematic Reference
Heated/Cooled Seat Schematics (See: Diagrams/Electrical Diagrams)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Heated Seats Description and Operation (See: Description and Operation)
Electrical Information Reference
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Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
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Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Connector
Repairs/Connector Repairs)
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Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/General
Electrical Diagnostic Procedures/Circuit Testing/Testing for Intermittent Conditions and Poor Connections)
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Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Wiring
Repairs/Wiring Repairs)
Scan Tool Reference
Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information
Circuit/System Verification
1. Ignition ON, observe the appropriate scan tool Driver Door Switch or Passenger Door Switch parameters listed below while pressing and releasing
the appropriate switch. The readings should change between Inactive and Active.
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Seat Back Heat Mode Sw.
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Seat Heat Mode Sw.
‹› If not the specified values, refer to the Heated Seat Switch component test. If the heated seat switch tests normal, replace the appropriate door
lock/window switch.
2. If all scan tool parameters test normal and there are no DTCs set, replace the MSM.
