Circuit Description
The body control module (BCM) commands the Intermittent mode of the wipers by switching the front wiper relay control circuit to ground at regular timed intervals. This provides low speed operation of the wiper motor during single swipes of the wipers. Each time the BCM grounds the circuit, the FRT WIPER relay energizes, which closes the switch side contacts of the relay in order to apply battery positive voltage to the windshield wiper motor via the windshield wiper switch MIST/OFF/LOW signal circuit and windshield wiper motor low speed circuit. The BCM monitors the voltage on the front wiper relay control circuit in order to determine when a failure has occurred. When the FRT WIPER relay is energized, the voltage level on the front wiper relay control circuit should be near 0 volts. When the FRT WIPER relay is de-energized, the voltage level should be high, near system voltage.
Control of the wipers during LO or HIGH speed switch settings is direct wired from the windshield wiper washer switch to the wiper motor and is not under the control of the BCM.
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 DTC
The ignition is in the RUN or ACC position.
Conditions for Setting the DTCs
The following conditions will cause these DTCs to set:
| • | B3717--The BCM detects short to ground or open. |
| • | B3718--The BCM detects a short to battery voltage. |
| • | For B3718 to set the wiper switch must be in Mist or Intermittent. |
| • | An open FRT WIPER 25 amp fuse |
| • | An open or short to ground in one of the WIPER SYSTEM relay circuits |
Action Taken When the DTC Sets
| • | If the front wiper relay control circuit is open or shorted to battery , the Intermittent wiper mode will not operate. |
| • | If the front wiper relay control circuit is shorted to ground, the wipers will always be on |
| • | If the FRT WIPER relay does not receive battery positive voltage from the WIPER SYSTEM relay, all wiper washer functions will be inoperative. |
| • | If any of the circuits that receive battery positive voltage from the FRT WIPER fuse are shorted to ground, the fuse will be open and all wiper washer functions will be inoperative. |
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. |
Diagnostic Aids
DTC B3717 indicates a probable failure of the front wiper relay control circuit. However, the DTC will also set if the WIPER SYSTEM relay fails to supply battery positive voltage to the FRT WIPER relay. This failure may be due to an open FRT WIPER 25 amp fuse, or a malfunction of the WIPER SYSTEM relay or associated circuits. All wiper washer functions will be inoperative for both the front windshield and the rear window. If the fuse is open, a short to ground in any one of the following circuits may be the cause:
| • | Accessory voltage circuit |
| • | Windshield washer pump control circuit |
| • | Windshield wiper motor high speed circuit |
| • | Windshield wiper motor low speed circuit |
| • | Windshield wiper switch Mist/Off/Low signal circuit |
| • | Windshield wiper switch pulse delay signal circuit |
| • | Windshield wiper motor park switch signal circuit |
| • | Rear wiper switch signal circuit |
| • | Rear window washer pump control circuit |
If there is no battery positive voltage supply to the FRT WIPER relay and an open FRT WIPER 25 amp fuse is not the cause, test the WIPER SYSTEM relay and associated circuits.
Test Description
The number below refers to the step number on the diagnostic table.
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 windshield wiper/washer system operate normally? | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 3 | ||||||||||||||||||
3 | Are the wipers always ON? | Go to Step 12 | Go to Step 4 | ||||||||||||||||||
4 | Inspect the FRT WIPER 25 amp fuse for an open. Is the fuse open? | Go to Step 5 | Go to Step 6 | ||||||||||||||||||
5 |
Did the new fuse open? | Go to Step 10 | Go to Step 15 | ||||||||||||||||||
6 |
Does the test lamp illuminate? | Go to Step 7 | Go to Step 11 | ||||||||||||||||||
Does the test lamp illuminate when you command the relay ON and go out when you command the relay OFF? | Go to Step 13 | Go to Step 8 | |||||||||||||||||||
8 | Test the front wiper relay control circuit for an open or a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 15 | Go to Step 9 | ||||||||||||||||||
9 | Inspect for poor connections at the harness connector of the 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 14 | ||||||||||||||||||
10 | Repair one of the following circuits for a short to ground:
Refer to Circuit Testing and Wiring Repairs . Did you complete the repair? | Go to Step 15 | -- | ||||||||||||||||||
11 | Repair an open or a high resistance in the battery positive voltage supply circuit of the FRT WIPER relay. Refer to Wiring Repairs or Connector Repairs . Did you complete the repair? | Go to Step 15 | -- | ||||||||||||||||||
12 | Repair a short to ground on the front wiper relay control circuit. Refer to Wiring Repairs or Connector Repairs . Did you complete the repair? | Go to Step 15 | -- | ||||||||||||||||||
13 | Replace the front wiper relay. Refer to Relay Replacement . Did you complete the replacement? | Go to Step 15 | -- | ||||||||||||||||||
14 | Replace the BCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 15 | -- | ||||||||||||||||||
15 |
Does the DTC reset? | Go to Step 2 | System OK | ||||||||||||||||||
