Chevrolet Silverado / GMC Sierra. Service manual — part 2702

Back Frame Replacement .

FRONT SEAT RECLINER ACTUATOR MOTOR REPLACEMENT

The front seat recliner actuator motor is serviced as part of the seat back assembly. If the actuator
motor needs to be replaced the entire seat back frame kit will need to be installed. Refer to Front
Seat Back Frame Replacement .

DESCRIPTION AND OPERATION

MEMORY SEATS DESCRIPTION AND OPERATION

Battery voltage is supplied to the driver seat module through a 25 A circuit breaker. The driver
seat module supplies the seat adjuster switch assembly with a battery positive reference voltage.
While the seat adjuster switches are in an inactive state the switch contacts are closed to the
adjuster switch common circuit. When a seat adjuster switch is pressed to an active state the
switch contact is closed to the reference voltage circuit. Battery voltage on a switch signal circuit
indicates to the driver seat module the switch status is active. Each seat adjuster motor is
controlled by the driver seat module through 2 motor control circuits. While the seat adjuster
motors are in an inactive state the motor control circuits are closed to ground circuit contacts
within the driver seat module. The driver seat module operates the seat adjuster motors by
switching one of a motors control circuits to battery voltage. The seat adjuster motors are
bidirectional and the direction of adjuster motor rotation is determined by which of the adjuster
motor control circuits is switched to battery voltage while the other remains grounded.

Memory Set/Recall Operation

The seat adjuster motors are equipped with internal position sensors. The adjuster motor position
sensors are monitored by the driver seat module and are used to determine the seat position when
storing or recalling memory settings. The driver seat adjuster motors use potentiometer type
position sensors. The position sensors are supplied with a 5-volt positive reference and ground
circuits from the driver seat module. The position sensor signal circuits return to an analog input
within the driver seat module. During adjuster motor operation the position sensor provides a
voltage change proportional to the change in revolution of the adjuster motor shaft. The driver
seat module monitors the voltage from the position sensor signal circuits to determine the adjuster
motor positions when storing or recalling memory seat position settings.

The memory recall switch assembly on the driver door provides inputs to the driver door module.
Battery voltage is supplied to the memory recall switch assembly from the driver door module.
When a RCL 1, RCL 2, or EXIT switch is pressed, the switch contacts close the appropriate
switch signal circuit to the battery voltage supply circuit within the memory recall switch

2008 Chevrolet Silverado 1500

2008 ACCESSORIES & EQUIPMENT Power Seats - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado

assembly. When the driver door module receives active switch signals from the memory recall
switch assembly, the appropriate commands are sent to the driver seat module using the GMLAN
Serial Data circuit. The Body Control Module software version determines the personalization
features available.

Memory seat recall operation is allowed only with the transmission selector lever in the PARK
position while the ignition is on. The transmission selector lever position data is provided to the
driver seat module by a message through the GMLAN Serial Data circuit.

POWER SEATS SYSTEM DESCRIPTION AND OPERATION

There are 2 options of power seat systems available in full size trucks. The first is 6 way driver
and passenger power seats without memory. The second is an 8-way driver seat plus 4-way
lumbar with memory, heat and optional cool function. While the passenger has 8-way power seats
with heat and optional cool function. For the driver memory seat operation, refer to Memory
Seats Description and Operation. Power seats without memory are completely controlled
through the power seat switch. Battery voltage is supplied to the power seat switch through the
power seat circuit breaker. While the seat adjuster switches are in an inactive state the switch
contacts are closed to the power seat switch ground circuit. When a power seat switch is pressed
to an active state the switch contact is closed to the battery voltage supply circuit. Each seat
adjuster motor is controlled by the power seat switch through 2 motor control circuits. The seat
adjuster motors are bidirectional and the direction of adjuster motor rotation is determined by
which of the adjuster motor control circuits is switched to battery voltage while the other remains
grounded.

2008 Chevrolet Silverado 1500

2008 ACCESSORIES & EQUIPMENT Power Seats - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado

2008 STEERING

Power Steering - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

SPECIFICATIONS

FASTENER TIGHTENING SPECIFICATIONS

Application

Specification

Metric

English

Pitman Arm Nut (at the Relay Rod)

62 N.m

46 lb ft

Pitman Arm Nut (at the Steering Gear)

250 N.m

184 lb ft

Power Brake Booster Inlet Hose Fitting

32 N.m

24 lb ft

Power Steering Fluid Cooler Bolt

9 N.m

80 lb in

Power Steering Fluid Reservoir Stud

58 N.m

44 lb ft

Power Steering Gear Inlet Hose Clip Bolt (6.6 L)

12 N.m

106 lb in

Power Steering Gear Inlet Hose Fitting

32 N.m

24 lb ft

Power Steering Gear Inlet Hose Retaining Plate
Bolt

12 N.m

106 lb in

Power Steering Gear Outlet Hose (6.6L)

32 N.m

24 lb ft

Power Steering Pump Bolt

50 N.m

37 lb ft

Power Steering Pump Bracket Bolt (4.3L)

41 N.m

30 lb ft

Power Steering Pump Bracket Bolt (4.8L, 5.3L,
6.0L, and 6.2L)

50 N.m

37 lb ft

Power Steering Pump Bracket Nut

41 N.m

30 lb ft

Power Steering Pump Fitting

75 N.m

55 lb ft

Power Steering Pump Front Bracket Bolt (6.6L)

50 N.m

37 lb ft

Power Steering Pump Rear Bracket Bolt (6.6L)

50 N.m

37 lb ft

Power Steering Pump Rear Bracket Nut (4.3L)

41 N.m

30 lb ft

Steering Gear Bolt (Non-Rack and Pinion)

150 N.m

110 lb ft

Steering Gear Bolt (Rack and Pinion Left Side)

200 N.m

148 lb ft

Steering Gear Bolt (Rack and Pinion Right Side)

100 N.m

74 lb ft

Steering Gear Cylinder Pipe Fitting

34 N.m

25 lb ft

Steering Gear Pitman Shaft and Housing Cover Bolt

62 N.m

46 lb ft

Steering Gear Pitman Shaft Lash Adjuster Lock Nut

49 N.m

36 lb ft

Steering Gear Rack Bearing Adjuster Plug Lock
Nut

68 N.m

50 lb ft

2008 Chevrolet Silverado 1500

2008 STEERING Power Steering - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

2008 Chevrolet Silverado 1500

2008 STEERING Power Steering - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

POWER STEERING PUMP SPECIFICATIONS

COMPONENT LOCATOR

POWER STEERING GEAR DISASSEMBLED VIEW (680 GEAR)

Steering Linkage Inner Tie Rod

100 N.m

74 lb ft

Steering Linkage Inner Tie Rod Nut

75 N.m

55 lb ft

Steering Linkage Outer Tie Rod Nut

60 N.m

44 lb ft

Stub Shaft Housing Bolt

62 N.m

46 lb ft

Vehicle

Engine Size

High Flow

(Liters per

Minute)

High Flow

(Gallons per

Minute)

Pressure

Relief (kPa)

Pressure

Relief (PSI)

C 1500

4.3L

11/12.5

2.9/3.3

9825/10514

1425/1525

K 1500

4.3L

10.2/11.7

2.7/3.1

9825/10514

1425/1525

C/K 15/25

4.8L
5.3L
6.0L
6.2L
6.6L

13.2/14.7

3.5/3.9

9825/10514

1425/1525

2008 Chevrolet Silverado 1500

2008 STEERING Power Steering - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado