B3718
DTC B3718CIRCUIT DESCRIPTION
The body control module (BCM) monitors the voltage level on the supply voltage circuit 1445 of the wiper relay. The voltage will be near system voltage while the relay is de-energized. When the front wiper switch is in intermittent or mist, voltage from the wiper switch is applied to the front wiper input of the BCM. The BCM responds by switching circuit 1445 to ground. This action energizes the front wiper relay, providing low speed operation of the wiper motor during single swipes. Control of the wiper during LO or HIGH speed switch settings is direct wired from the wiper switch to the wiper motor and is not under the control of the BCM.
CONDITIONS FOR RUNNING THE DTC
The ignition is in the RUN or ACC position.
CONDITIONS FOR SETTING THE DTCS
The following conditions will cause these DTCs to set:
- DTC B3717, the BCM detects short to ground or open.
- For DTC B3717 the wiper switch does not need to be ON.
- DTC B3718, the BCM detects a short to battery voltage.
- For DTC B3718 to set the wiper switch must be in mist or intermittent.
ACTION TAKEN WHEN THE DTC SETS
- The windshield wipers will be disabled until the conditions mentioned above are no longer present for an open or short to battery.
- The wipers will always be on if the front wiper relay control circuit, circuit 1445, is shorted to ground.
- No indicator will illuminate on I/P.
- If circuit 1445 is shorted to battery, the BCM output will go into a protective state. The BCM output will not allow itself to be activated, switch closed, for as much as three minutes.
CONDITIONS FOR CLEARING THE DTC
- This DTC will change from current to history when the fault is no longer present.
- A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.
TEST DESCRIPTION
Steps 1-12:
The numbers below refer to the step numbers on the diagnostic table.
10. Listen for an audible click when the wiper 1 relay operates. Command both the ON and OFF states. Repeat the commands, as necessary.
11. Verifies that the BCM is providing voltage to the wiper 1 relay.