When operation of the rear wiper is selected, battery voltage from the rear wiper switch is applied to the rear wiper switch signal input of the body control module (BCM) circuit. 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.
This diagnostic procedure supports the following DTC:
DTC B3722 Rear Wiper Relay Drive Circuit Low
The ignition is in RUN or ACC position.
• | The rear wiper relay control circuit is shorted to ground or open. |
• | The accessory voltage circuit to the coil side of the relay is open . |
• | The accessory voltage circuit is shorted to ground between the fuse and the rear wiper motor. |
• | The rear window wiper motor control circuit is shorted to ground. |
• | The RR WIPER 15-amp fuse is open. |
Service (wrench) light will illuminate.
• | 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. |
• | Inspect for poor connection at the BCM. Inspect harness connectors for backed out terminals, improper terminal mating, broken connector locks, improperly formed or damaged terminals and poor terminal-to-wire connection, terminal crimped over wire insulation and not conductors. |
• | If the rear wiper relay control circuit is open, the rear wipers will be inoperative. |
• | If the rear wiper relay control circuit is shorted to ground, the rear wipers will always be ON. |
• | If, either the accessory voltage circuit, or the rear window wiper motor control circuit is shorted to ground, the RR WIPER fuse will open and the rear wipers will be inoperative. |
• | Inspect the wiring harness for damage. Inspect for broken or chaffed insulation. |
• | If the fault is suspected to be intermittent, wiggling the harness wiring may help in locating 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 | |||||
2 |
Does the test lamp illuminate for both accessory voltage circuits? | Go to Step 3 | Go to Step 4 | ||||
3 |
Does the test lamp illuminate when you command ON and go out when you command OFF? | Go to Step 8 | Go to Step 7 | ||||
4 | Inspect for an open RR WIPER 15-amp fuse. Is the fuse open? | Go to Step 5 | Go to Step 11 | ||||
5 |
Does the RR WIPER fuse open again? | Go to Step 6 | Go to Step 15 | ||||
6 | Test the following circuits of the rear wiper motor for a short to ground:
Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 15 | Go to Step 10 | ||||
7 | Test the rear wiper relay control circuit for an open or a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 15 | Go to Step 9 | ||||
8 | Inspect for poor connections and terminal damage at the UHFB. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 15 | Go to Step 14 | ||||
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 15 | Go to Step 13 | ||||
10 | Inspect for poor connections at the harness connector of the rear wiper motor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 15 | Go to Step 12 | ||||
11 | Repair the open in the accessory voltage supply circuit of the rear wiper relay. Refer to Connector Repairs and Wiring Repairs . Did you complete the repair? | Go to Step 15 | -- | ||||
12 | Replace the rear wiper motor. Refer to Liftgate Wiper Motor Replacement . Did you complete the replacement? | Go to Step 15 | -- | ||||
13 | Replace the BCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 15 | -- | ||||
14 | Replace the rear wiper relay. Refer to Relay Replacement . Did you complete the replacement? | Go to Step 15 | -- | ||||
15 |
Does the DTC reset? | Go to Step 2 | System OK |