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 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.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B3722 Rear Wiper Relay Drive Circuit Low
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 ground or open. |
| • | Rear wiper relay output if OFF. |
Actions Taken When the DTC Sets
Service (wrench) light will illuminate.
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
| • | Check for poor connection at the BCM. Inspect harness connectors for backed out terminals, improper terminal mating, broken connectors 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. |
| • | Inspect wiring harness for damage. Check for broken or chaffed insulation. |
| • | If fault is suspected to be intermittent, wiggling harness wiring may help in locating fault. |
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Wiper/Washer Schematics Connector End View Reference: Master Electrical Component List in Wiring Systems | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
2 |
Does relay follow command? | Go to Diagnostic Aids | Go to Step 3 |
3 |
Does the test lamp illuminate? | Go to Step 4 | Go to Step 5 |
4 | Does the test lamp follow the scan tool command? | Go to Step 13 | Go to Step 8 |
5 | Connect the test lamp between the rear wiper motor switch and ground at the rear wiper relay location. Does the test lamp illuminate? | Go to Step 6 | Go to Step 7 |
6 |
Is there continuity in the circuit? | Go to Step 12 | Go to Step 11 |
7 | Check for open RR wiper 15 A fuse. Is the fuse open? | Go to Step 10 | Go to Step 9 |
8 | Test the rear wiper relay control circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 12 |
9 | Repair an open in the rear wiper motor switch circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 14 | -- |
10 | Repair a short to ground in the rear wiper motor switch circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 14 | -- |
11 | Repair an open in the rear wiper relay control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 14 | -- |
12 | Replace the BCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | Go to Step 14 | -- |
13 | Replace the rear wiper relay. Refer to Relay Replacement in Wiring Systems. Did you complete the replacement? | Go to Step 14 | -- |
14 |
Does the DTC reset? | Go to Step 2 | System OK |
