GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 TrailBlazer - 2WD 🢒 Accessories 🢒 Navigation Systems 🢒 DTC B3810 or B3811

Circuit Description

Battery positive voltage is supplied to the coil and switch sides of the rear washer and headlamp washer relays. The body control module (BCM) energizes a relay by grounding the relay coil through the relay control circuit. When a relay is energized, the relay switch is closed and battery positive voltage is supplied to the washer pump control circuit.

DTC Descriptors

This diagnostic procedure supports the following DTCs:

    • DTC B3810 Headlamp Washer Relay Circuit
    • DTC B3811 Rear Washer Relay Circuit

Conditions for Running the DTC

Battery voltage must be between 9-16 volts.

Conditions for Setting the DTC

B3810

The headlamp washer relay control circuit is shorted to ground or open while the relay is de-energized, or shorted to B+ while the relay is energized.

B3811

The rear washer relay control circuit is shorted to ground or open while the relay is de-energized, or shorted to B+ while the relay is energized.

Action Taken When the DTC Sets
    • The DTC will be current for as long as the fault is present.
    • The headlamp washers will be disabled for as long as the B3810 is current.
    • The rear washers will be disabled for as long as the B3811 is current.

Conditions for Clearing the DTC
    • A current DTC clears when the malfunction is no longer present.
    • A history DTC clears when the module ignition cycle counter reaches the reset threshold, without a repeat of the malfunction.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step tests for battery positive voltage to the high side of the relay coil. The WASH fuse supplies power to the headlamp washer and rear washer relays.

    2.

  2. This step tests the ability of the BCM to energize the relay.

    3.

  3. This step tests for a condition which causes the relay to remain energized at all times.

Step

Action

Yes

No

Schematic Reference: Wiper/Washer Schematics

Connector End View Reference: Wiper/Washer Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2
  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, command the relay ON and OFF.
  4. Refer to Electrical Center Identification Views for relay location.

Does the relay turn ON and OFF with each command?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Disconnect the relay. Refer to Electrical Center Identification Views for relay location.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the battery positive voltage circuit of the relay with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 4

Go to Step 10

4

  1. Connect a test lamp between the control circuit of the relay and the battery positive voltage circuit of the relay. Refer to Electrical Center Identification Views for relay location.
  2. With a scan tool, command the relay ON and OFF .

Does the test lamp turn ON and OFF with each command?

Go to Step 8

Go to Step 5

5

Does the test lamp remain illuminated with each command?

Go to Step 7

Go to Step 6

6

Test the control circuit of the relay for a short to voltage or an open. Refer to the following:

    •  Circuit Testing
    •  Wiring Repairs

Did you find and correct the condition?

Go to Step 13

Go to Step 9

7

Test the control circuit of the relay for a short to ground. Refer to the following:

    •  Circuit Testing
    •  Wiring Repairs

Did you find and correct the condition?

Go to Step 13

Go to Step 9

8

Test the control circuit of the relay for a short to ground. Refer to the following:

    •  Circuit Testing
    •  Wiring Repairs

Did you find and correct the condition?

Go to Step 13

Go to Step 11

9

Inspect for poor connections at the harness connector of the body control module (BCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 13

Go to Step 12

10

Repair the battery positive voltage circuit of the relay. Refer to Wiring Repairs .

Did you complete the repair?

Go to Step 13

--

11

Replace the relay. Refer to Electrical Center Identification Views for relay location.

Did you complete the replacement?

Go to Step 13

--

12

Replace the BCM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 13

--

13
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the system in order to verify the repair.

Does the DTC reset?

Go to Step 2

System OK