Circuit Description
When operation of the rear wiper is selected, battery voltage from the rear wiper switch is applied to the rear wiper switch signal input circuit of the body control module (BCM). The BCM responds by switching the rear wiper relay control circuit to ground. This action energizes the rear wiper relay, providing power to the rear wiper motor.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B3723 Rear Wiper Relay Drive Circuit High
Conditions for Running the DTC
Ignition is in RUN or ACC position.
Conditions for Setting the DTC
| • | The rear wiper relay control circuit is shorted to battery. |
| • | The rear wiper relay output is ON. |
Actions Taken When the DTC Sets
| • | The service (wrench) light will illuminate. |
| • | The rear wipers are inoperative. |
Conditions for Clearing the DTC
| • | A current DTC clears when the fault is no longer present. |
| • | A history DTC clears when the module ignition cycle counter reaches the reset threshold, without a repeat of the fault. |
Diagnostic Aids
| • | When the BCM has been requested to activate the rear wiper relay, the BCM switches the rear wiper relay control circuit to ground. However, if the circuit is shorted to battery voltage, high current flow will result and the BCM output will go into a protective state. The BCM output will not allow itself to be activated for as much as 3 minutes. |
| • | Inspect the harness connectors at the BCM for improper terminal mating, broken connector locks, and improperly formed or damaged terminals. |
| • | Inspect wiring harness for damage. Inspect for broken or chaffed insulation. |
| • | Review all fail information as this may assist in determining the conditions when the fault occurs. |
| • | If the fault is suspected to be intermittent, wiggling the harness wiring may help in locating the fault. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step will determine if the rear wiper relay is internally shorted to battery voltage. Once you have disconnected the relay, you should be able to clear DTC B3723 with no recurrence. It is, however, normal for DTC B3722 to set while the relay is disconnected.
-
This step will determine if the rear wiper relay control circuit is shorted to battery voltage, or if the BCM is at fault.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Wiper/Washer Schematics Connector End View Reference: Master Electrical Component List | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
|
Important: DTC B3722 may set as a result of disconnecting the REAR WIPER Relay.
Does DTC B3723 clear? | Go to Step 5 | Go to Step 3 | |
Test the rear wiper relay control circuit for a short to battery. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 6 | Go to Step 4 | |
4 | Replace the body control module (BCM). Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 6 | -- |
5 | Replace the rear wiper relay. Refer to Relay Replacement . Did you complete the replacement? | Go to Step 6 | -- |
6 |
Does the DTC reset? | Go to Step 2 | System OK |
