Headlamp Washer

The Body Control Module (BCM) controls the washer motor based on an input from the windshield wiper washer switch. The BCM monitors the washer switch through the windshield washer switch signal circuit. When the WASH switch is closed, ground is supplied to the front washer switch signal circuit. When this is seen, the BCM will command the front washer fluid pump and the low speed wipers on. When Headlamp Wash Equipped, the headlamps shall be sprayed with wash fluid as a result of an extended Windshield Wash Switch Activation. In order to preserve wash fluid, the feature shall only be allowed to activate if the Low or High Beam Headlamps are active. In addition, after the initial Headlamp Wash operation has been performed, additional headlamp washes shall not be performed for the next 4 Windshield Wash activations or for 48 hours whichever comes first.

Rear Washer

When the Body Control Module detects that the Rear wiper / wash switch has activated the momentary Wash switch, it activates a High Side Drive output which supplies Battery to the coil of the Rear Washer Pump Relay. This energizes the Relay, which switches Battery Power to the Washer Pump Motor. The BCM will also activate continuous Low Speed Windshield Wipers as described above. This Washer and Wiper operation shall be continued so long as the switch remains active. Upon termination the Rear Wash Motor will be deactivated and the Wiper shall move to its Park Position and deactivate.

Washer operation is suspended.

The headlamp wash feature shall only be allowed to be activated if the low or high beam headlamps are active too.

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

Scan Tool Reference

Control Module References for diagnostic tester information

DTC B3810

Operate the washers using the S78 Turn Signal /Multifunction Switch. Verify the G16 Headlamp Washer Fluid Pump activates.

DTC B3811

Operate the washers using the S78 Turn Signal / Multifunction Switch. Verify the G24 Windshield Washer Fluid Pump activates.

DTC B3810

1. Ignition OFF, disconnect the KR2 Headlamp Washer Fluid Pump Relay.
2. Connect a test lamp between the control circuit terminal 86 and ground.
3. Ignition ON, command the headlamp washer ON and OFF using the wiper switch. The test lamp should turn ON and OFF when changing between the commanded states.

⇒	If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K9 Body Control Module (BCM).

⇒	If the test lamp is always OFF, test for a short to ground or an open/high resistance on the control circuit. If the circuit tests normal, replace the K9 Body Control Module (BCM).

4. If all circuits test normal, test or replace the KR2 Headlamp Washer Fluid Pump Relay.

DTC B3811

1. Ignition OFF, disconnect the harness connector X2 at the X50A Fuse Block - Underhood Primary.
2. Connect a test lamp between the control circuit terminal X2 59 and ground.
3. Ignition ON, command the rear washer ON and OFF using the S78 Turn Signal /Multifunction Switch. The test lamp should turn ON and OFF when changing between the commanded states.

⇒	If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K9 Body Control Module (BCM).

⇒	If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module (BCM).

4. If all circuits test normal, test or replace the X50A Fuse Block - Underhood Primary.

DTC B3810

Dynamic Test

1. Install a 30 A fused jumper wire between the relay terminals 85, 87and 12 V. Install a jumper wire between the relay terminal 86 and ground.
2. Connect a test lamp between relay terminal 30 and ground.
3. Observe the test lamp turns ON and OFF by grounding the relay terminal 86 briefly several times.

⇒	If the function does not perform as specified, replace the KR2 Headlamp Washer Fluid Pump Relay.

DTC B3810

Relay Test

1. Ignition OFF, disconnect the KR2 Headlamp Washer Fluid Pump Relay.
2. Test for 60-200 Ω between terminals 85 and 86.

⇒	If the resistance is not within the specified range, replace the KR2 Headlamp Washer Fluid Pump Relay.

3. Test for infinite resistance between the following terminals:

•

30 and 86

•

30 and 87

•

30 and 85

•

85 and 87

⇒	If not the specified value, replace the KR2 Headlamp Washer Fluid Pump Relay.

4. Test for less than 5 Ω between terminals 30 and 87A.

⇒	If greater than the specified value, replace the KR2 Headlamp Washer Fluid Pump Relay.

5. Install a 10 A fused jumper wire between relay terminal 85 and 12 V. Install a jumper wire between relay terminal 86 and ground. Test for less than 5 Ω between terminals 30 and 87.

⇒	If greater than the specified range, replace the KR2 Headlamp Washer Fluid Pump Relay.

DTC B3811

Output Control Tests

Ignition ON, command the Rear Washer ON and OFF with a scan tool. Observe that the KR6 Rear Window Washer Pump Relay clicks and the G24 Windshield Washer Fluid Pump runs.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for BCM replacement, setup, and programming

Relay Replacement

LInk X for UEC replacement.