Service Information

Orlando

DTC B3715 or B3875

Diagnostic Instructions

•	Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

•	Review Strategy Based Diagnosis for an overview of the diagnostic approach.

•	Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC B3715 01: Windscreen Wiper Relay Circuit Short to Battery

DTC B3715 02: Windscreen Wiper Relay Circuit Short to Ground

DTC B3715 04: Windscreen Wiper Relay Circuit Open

DTC B3875 01: Windscreen Wiper High Speed Relay Circuit Short to Battery

DTC B3875 02: Windscreen Wiper High Speed Relay Circuit Short to Ground

DTC B3875 04: Windscreen Wiper High Speed Relay Circuit Open

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Windscreen Wiper High Speed Relay B+	1, 2	1, 2	--	--
Windscreen Wiper Switch Low Signal	1	1	1	--
Windscreen Wiper Switch High Signal	4	2	2	--
Windscreen Wiper Motor Park Switch Signal	3	3	--	--
Front Wiper Relay Control	B3715 02	B3715 04	B3715 01	-
Windscreen Wiper High Speed Relay Control	B3875 02	B3875 04	B3875 01	-
Windscreen Wiper High Speed Relay Control	2	2	4	--
Front Wiper Motor Low Speed Control	1	1	4	--
Windscreen Wiper Switch Low Reference	--	1, 2	1, 2	--
Windscreen Wiper Motor Ground	--	1, 2, 3	--	--
Front Wiper Relay Ground	--	1	--	--
1. Delay or Low Speed Wipers Inoperative 2. High Speed Wipers Inoperative 3. Wipers Do Not Park 4. Wipers Always ON

Circuit/System Description

The Body Control Module (BCM) controls the windscreen wiper motor based on input from the windscreen wiper/washer switch. The BCM monitors the wiper/washer switch through two separate signal circuits and a ground circuit. The windscreen wiper switch high signal circuit is used to determine high speed wiper operation, the windscreen wiper switch low signal is used to determine low speed, intermittent, and mist operation through the use of a resistor ladder, and windscreen washer switch signal circuit is used to determine washer operation.

The BCM controls the windscreen wiper motor through two output controls, controlling two relays which determine the desired wiper speed, high or low.

Conditions for Running the DTC

•	The DTC runs only when a wiper output is actively being requested by the BCM.

•	The system voltage is between 9–16 V.

Conditions for Setting the DTC

•	A short to voltage is detected in the Front Wiper Relay control circuit or in the High Speed Relay control circuit.

•	A short to ground or an open/high resistance is detected in the Front Wiper Relay control circuit or in the High Speed Relay control circuit.

Action Taken When the DTC Sets

The BCM will not activate the wiper output.

Conditions for Clearing the DTC

•	A current DTC will clear when the condition for setting the fault is no longer seen.

•	A history DTC will clear after 50 consecutive ignition cycles without a fault present.

Reference Information

Electrical Information Reference

•	Circuit Testing

•	Connector Repairs

•	Testing for Intermittent Conditions and Poor Connections

•	Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

•	Ignition ON, S82 Windscreen Wiper/Washer Switch in LOW position. Verify the front wipers are cycling at the low speed.

•	Ignition ON, S82 Windscreen Wiper/Washer Switch in the HIGH position. Verify the front wipers are cycling at the high speed.

Circuit/System Testing

DTC B3715

Ignition OFF, disconnect the KR12B Windscreen Wiper Relay.
Connect a test lamp between the control circuit terminal 86 and ground.
Ignition ON, command the low speed wipers ON and OFF using the S82 Windscreen Wiper/Washer Switch. The test lamp should turn ON and OFF when changing between the commanded states.

⇒	If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K9 Body Control Module.

⇒	If the test lamp is always OFF, test for a short to ground or an open/high resistance on the control circuit. If the circuit tests normal, replace the K9 Body Control Module.

If all circuits test normal, test or replace the KR12B Windscreen Wiper Relay.

DTC B3875

Ignition OFF, disconnect the KR12C Windscreen Wiper Speed Control Relay.
Connect a test lamp between the control circuit terminal 86 and B+.
Ignition ON, command the high speed wipers ON and OFF using the S82 Windscreen Wiper/Washer Switch. The test lamp should turn ON and OFF when changing between the commanded states.

⇒	If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the K9 Body Control Module.

⇒	If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module.

If all circuits test normal, test or replace the KR12C Windscreen Wiper Speed Control Relay.

Component Testing

DTC B3715 - Relay Test

Ignition OFF, disconnect the KR12B Windscreen Wiper Relay.
Test for 60-200 Ω between terminals 85 and 86.

⇒	If the resistance is not within the specified range, replace the KR12B Windscreen Wiper Relay.

Test for infinite resistance between the following terminals:

•

30 and 86

•

30 and 87

•

30 and 85

•

85 and 87

⇒	If not the specified value, replace the KR12B Windscreen Wiper Relay.

Test for less than 5 Ω between terminals 30 and 87A.

⇒	If greater than the specified value, replace the KR12B Windscreen Wiper Relay.

Install a 10 A fused jumper wire between relay terminal 85 and 12 V. Install a jumper wire between relay terminal 86 and ground. Test for less than 5 Ω between terminals 30 and 87.

⇒	If greater than the specified range, replace the KR12B Windscreen Wiper Relay.

DTC B3875 - Relay Test

Ignition OFF, disconnect the KR12C Windscreen Wiper Speed Control Relay.
Test for 60-200 Ω between terminals 85 and 86.

⇒	If the resistance is not within the specified range, replace the KR12C Windscreen Wiper Speed Control Relay.

Test for infinite resistance between the following terminals:

•