Circuit Description
The body control module (BCM) controls and monitors the state of the ON/OFF wiper relay control circuit. When the windshield wiper switch is placed in to a low speed setting, a signal is applied to the BCM. The BCM then applies battery positive voltage to the coil side of the ON/OFF WPR relay through the relay control circuit. This energizes the relay, allowing battery positive voltage from the FRT/WPR fuse through the switched side of the ON/OFF WPR relay through the HI/LOW WPR relay and to the windshield wiper motor. Ground is applied at all times to the coil sides of the wiper relays and the windshield wiper motor from G105.
DTC Descriptors
This diagnostic procedure supports the following DTCs:
| • | DTC B3717 Front Wiper Relay Drive Circuit Low |
| • | DTC B3718 Front Wiper Relay Drive Circuit High |
Conditions for Running the DTCs
| • | The ignition is ON. |
| • | The ignition voltage is between 9-18.5 volts. |
Conditions for Setting the DTCs
The following conditions will cause these DTCs to set:
| • | DTC B3717, the BCM detects a low voltage level on the supply circuit of the wiper micro relay for 1 second when the relay is energized. |
| • | DTC B3718, the BCM detects a high voltage level on the supply circuit of the wiper micro relay for 1 second when the relay is de-energized. |
Action Taken When the DTC Sets
The BCM de-energizes the wiper micro relay, until the wiper switch is turned OFF and ON.
Conditions for Clearing the DTCs
| • | DTC B3717 will change from current to history when the windshield wiper switch is turned OFF and ON, and the condition is no longer present. |
| • | DTC B3718 will change from current to history when the condition is no longer present. |
| • | A history DTC will clear after 100 ignition cycles, without a repeat of the malfunction. |
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 | |
2 |
Do the windshield wipers operate? | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 3 |
3 |
Does the test lamp illuminate? | Go to Step 8 | Go to Step 4 |
4 |
Does the test lamp illuminate? | Go to Step 5 | Go to Step 6 |
5 |
Does the test lamp illuminate? | Go to Step 9 | Go to Step 7 |
6 | Test for a poor connection, an open, or short to ground in the ON/OFF wiper relay control circuit. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 12 | Go to Step 10 |
7 | Test for a poor connection or an open in the ground circuit of the ON/OFF WPR relay. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 12 | Go to Step 11 |
8 | Repair a short to battery positive voltage in the ON/OFF wiper relay control circuit. Refer to Circuit Testing and Wiring Repairs . Did you complete the repair? | Go to Step 12 | -- |
9 |
Does the DTC reset? | Go to Step 11 | Go to Step 12 |
10 | Replace the body control module (BCM). Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 12 | -- |
11 | Replace the underhood electrical center. Refer to Underhood Electrical Center or Junction Block Replacement . Did you complete the replacement? | Go to Step 12 | -- |
12 |
Does the DTC reset? | Go to Step 2 | System OK |
