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Chevrolet Silverado / GMC Sierra. Manual - part 3004
Component Connector End Views
Description and Operation
Wiper/Washer System Description and Operation
Electrical Information Reference
Circuit Testing
Connector Repairs
Testing for Intermittent Conditions and Poor Connections
Wiring Repairs
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Ignition ON, wiper switch in LOW position. Verify the windshield wipers are cycling at the low
speed.
Circuit/System Testing
1. Ignition OFF, disconnect the X5 harness connector at the BCM.
2. Ignition ON, verify that the low speed wipers are not on.
If the low speed wipers are on, test the WIPER CONTROL relay control circuit
terminal 20 for a short to voltage. If the circuit tests normal, replace the underhood
fuse block.
3. Install a 10A fused jumper wire between the WIPER CONTROL relay control circuit
terminal 20 and B+. Verify the low speed wipers are on.
If the low speed wipers are not on, test the relay control circuit for an open/high
resistance or short to ground. If the circuit tests normal replace the underhood fuse
block.
4. If all circuits test normal, replace the BCM.
Repair Procedures
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
2008 Chevrolet Silverado 1500
2008 ACCESSORIES & EQUIPMENT Wipers and Washers - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &
Silverado
Underhood Electrical Center or Junction Block Replacement
Control Module References for BCM replacement, setup, and programming
DTC B3873
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.
DTC Descriptor
DTC B3873 00
Front Washer Relay Circuit
Diagnostic Fault Information
Circuit/System Description
The windshield washer function is controlled by the body control module (BCM). When the
washer switch is pressed, ground is applied through the switch contacts and the signal circuit to
the BCM indicating the wash request. The BCM then applies ground through the control circuit
to the coil side of the FRT WASH relay energizing the relay. With the relay energized, battery
voltage from the FRT WPR fuse is applied through the switch contacts of the relay, the FRT
Circuit
Short to
Ground
Open/High
Resistance
Short to
Voltage
Signal
Performance
Windshield Washer Switch
Signal
2
1
1
-
Windshield Washer Fluid
Pump Control
1
1
2
-
FRT WASH Relay Control
2
1
B3873 00
-
Windshield Washer Switch
Low Reference
-
1
-
-
Windshield Washer Fluid
Pump Ground
-
1
-
-
1. Washer Inoperative
2. Washers Always ON
2008 Chevrolet Silverado 1500
2008 ACCESSORIES & EQUIPMENT Wipers and Washers - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &
Silverado
WASH fuse, and the control circuit to the windshield washer fluid pump.
Conditions for Running the DTC
This DTC can set only when the output is actively being requested by the BCM.
Conditions for Setting the DTC
This DTC sets if the BCM detects a short to B+ in the windshield washer pump relay control
circuit.
Action Taken When the DTC Sets
The BCM will not activate the output.
Conditions for Clearing the DTC
The current DTC will become history when the request for the output is removed or when
the condition for setting the fault is corrected.
The history DTC will clear after 50 consecutive ignition cycles without a fault present.
Reference Information
Schematic Reference
Wiper/Washer Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Wiper/Washer System Description and Operation
Electrical Information Reference
Circuit Testing
Connector Repairs
Testing for Intermittent Conditions and Poor Connections
Wiring Repairs
2008 Chevrolet Silverado 1500
2008 ACCESSORIES & EQUIPMENT Wipers and Washers - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &
Silverado
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Operate the washers using the WASH switch. Verify the washer pump activates.
Circuit/System Testing
1. Ignition OFF, disconnect the X4 harness connector at the BCM.
2. Ignition ON, verify the windshield washer pump is not on.
If the windshield washer pump is on, test the windshield washer pump relay control
circuit terminal 15 for a short to ground. If the circuit tests normal replace the
underhood fuse block.
3. Install a 10A fused jumper wire between the relay control circuit terminal 15 and ground.
Verify the windshield washer pump is on.
If the windshield washer pump is not on, test the relay control circuit for a short to
voltage or an open/high resistance. If the circuit tests normal replace the underhood
fuse block.
4. If all circuits test normal, replace the BCM.
Repair Procedures
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Underhood Electrical Center or Junction Block Replacement
Control Module References for BCM replacement, setup, and programming
DTC B3875
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.
DTC Descriptor
DTC B3875 00
2008 Chevrolet Silverado 1500
2008 ACCESSORIES & EQUIPMENT Wipers and Washers - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &
Silverado
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