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Chevrolet Silverado / GMC Sierra. Manual - part 2696
setup
SYMPTOMS - POWER SEATS
1. Perform the Diagnostic System Check - Vehicle before using the Symptom Tables in
order to verify that all of the following are true:
There are no DTCs set.
The control modules can communicate via the serial data link.
2. Review the system operation in order to familiarize yourself with the system functions.
Refer to the following system descriptions:
Memory Seats Description and Operation
Power Seats System Description and Operation
Visual/Physical Inspection
Inspect for aftermarket devices which could affect the operation of the system. Refer to
Checking Aftermarket Accessories .
Inspect the easily accessible or visible system components for obvious damage or conditions
which could cause the symptom.
Intermittent
Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to
Testing for Intermittent Conditions and Poor Connections .
Symptom List
Refer to a symptom diagnostic procedure from the following list in order to diagnose the
symptom:
Memory Seat Feature Inoperative
Power Seat Inoperative (w/o Memory) or Power Seat Inoperative (w/Memory)
MEMORY SEAT FEATURE INOPERATIVE
Diagnostic Instructions
IMPORTANT: The following steps must be completed before using the symptom
tables.
2008 Chevrolet Silverado 1500
2008 ACCESSORIES & EQUIPMENT Power Seats - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &
Silverado
Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic approach.
Diagnostic Procedure Instructions provides an overview of each diagnostic category.
Diagnostic Fault Information
Circuit/System Description
Battery positive voltage is supplied to the memory function switch from the driver door switch
(DDS). When a memory switch is pressed, battery voltage is applied through the switch contacts,
a series of resistors, and thorough the memory switch signal circuit to the DDS. The door control
module then sends a message via the GMLAN serial data line to the memory seat module (MSM)
indicating the memory recall request. The MSM then commands the appropriate seat motors to
move to the pre-recorded seat positions stored in memory in response to the switch input.
Reference Information
Schematic Reference
Driver Seat Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Memory Seats Description and Operation
Electrical Information Reference
Circuit Testing
Connector Repairs
Circuit
Short to
Ground
Open/High
Resistance
Short to
Voltage
Signal
Performance
Memory Switch Signal
1
1
1
-
Memory Switch Supply
Voltage
-
1
-
-
1. Memory Seat Feature Inoperative
2008 Chevrolet Silverado 1500
2008 ACCESSORIES & EQUIPMENT Power Seats - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &
Silverado
Testing for Intermittent Conditions and Poor Connections
Wiring Repairs
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
1. Verify that all manual power seat and lumbar functions operate as described in the
description and operation.
2. Verify that memory positions for driver 1 and driver 2 have been recorded to memory, by
observing the scan tool Driver Position Module, Memory Data 1 and Memory Data 2
parameters.
Circuit/System Testing
1. Ignition ON, verify the scan tool Memory Recall Switches parameter is approximately 2.74
volts while pressing the memory 1 switch.
If the parameter is not the specified value, refer to Memory Switch component test
below. If the switch tests normal, replace the driver door switch.
2. Verify the scan tool Memory Recall Switches parameter is approximately 1.78 volts while
pressing the memory 2 switch.
If the parameter is not the specified value, replace the memory switch.
3. Verify the scan tool Memory Recall Switches parameter is approximately 0.96 volt while
pressing the EXIT switch.
If the parameter is not the specified value, replace the memory switch.
4. If all circuits test normal, replace the memory seat module.
Component Testing
Memory Switch
1. Disconnect the X4 harness connector at driver door switch.
2. Test for infinite resistance between the memory switch signal circuit terminal 5 and the
switch supply voltage circuit terminal 14.
If not infinite, replace the memory switch.
3. Test the resistance between terminal 14 and terminal 5 while pressing the memory 1,
memory 2, and EXIT buttons. Compare the resistance readings to the values in the Memory
2008 Chevrolet Silverado 1500
2008 ACCESSORIES & EQUIPMENT Power Seats - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &
Silverado
Switch Values table below.
If the resistance is not within the specified range, replace the memory switch.
Memory Switch Values
Repair Procedures
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Driver Seat Adjuster Memory Switch Replacement (Crew Cab)
Control Module References for MSM of DDS replacement, programming, and setup
POWER SEAT INOPERATIVE (W/O MEMORY)
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic approach
Diagnostic Procedure Instructions provides an overview of each diagnostic category
Diagnostic Fault Information
Switch Position
Resistance
Idle
Infinite
Memory 1
2.03K-2.49K ohms
Memory 2
3.83K-4.69K ohms
Exit
9.32K-10.18K ohms
Circuit
Short to
Ground
Open/High
Resistance
Short to
Voltage
Signal
Performance
Lumbar Switch B+
1, 2
2
-
-
Power Seat Switch B+
1, 2
1
-
-
Front Vertical Motor Front
Down Control
1
1
-
-
Front Vertical Motor Front Up
Control
1
1
-
-
Horizontal Motor Forward
Control
1
1
-
-
Horizontal Motor Rearward
Control
1
1
-
-
2008 Chevrolet Silverado 1500
2008 ACCESSORIES & EQUIPMENT Power Seats - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &
Silverado
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