B1435

What Does Code B1435 Mean?

DTC B1435 indicates an open circuit condition detected within the control circuit for the wiper high/low speed relay coil. This code is typically set by the vehicle’s Body Control Module (BCM), Integrated Power Module (IPM), or a dedicated Front Control Module (FCM), which are responsible for monitoring and controlling various body electrical systems, including the windshield wiper system. The control module supplies voltage or ground to energize the relay coil, and it actively monitors the resistance or current flow through this circuit. When the module attempts to activate the relay, it expects a specific current draw and resistance across the coil. If the module detects an abnormally high resistance, indicating a loss of continuity (an open circuit), or a current draw significantly below its programmed threshold, it registers this condition and sets code B1435. This open circuit prevents the relay coil from being properly energized, thereby inhibiting the switching action required to deliver power for high or low speed wiper operation, depending on the system’s specific relay configuration.

Common Symptoms

• Wipers do not operate at high speed: The most direct symptom, as the relay responsible for the high-speed circuit cannot be activated.
• Wipers do not operate at low speed: Similarly, if the relay is designated for low-speed control.
• Wipers operate only at intermittent or a single speed: If the high/low speed functions are controlled by a separate relay that is faulty.
• Wipers do not operate at all: In some systems, this relay may be critical for any wiper function beyond park.
• Intermittent or erratic wiper operation: May occur if the open circuit is partial or an intermittent connection.
• “Service Wipers” or other dashboard warning message: Specific warning lights or messages may appear on the instrument cluster, though a B-code typically doesn’t trigger the Malfunction Indicator Lamp (MIL) directly unless tied to a safety-critical system.

What Causes the Code B1435?

• Faulty Wiper Hi/Low Speed Relay: An internal open circuit within the relay coil itself, preventing it from being energized.
• Open Circuit in Wiring Harness: A break, fraying, corrosion, or poor connection in the electrical wiring leading to or from the wiper high/low speed relay coil, either on the power supply side or the ground control side from the BCM/IPM.
• Corroded or Loose Relay Socket Connections: Poor pin tension, contamination, or oxidation within the relay socket terminals, preventing proper electrical contact with the relay pins.
• Blown Fuse: A fuse supplying power to the relay coil circuit can create an open condition, effectively preventing the coil from receiving power.
• Faulty Body Control Module (BCM)/Integrated Power Module (IPM): An internal fault within the control module’s relay driver circuit, which is responsible for supplying power or ground to energize the relay coil. This is less common but a possibility.

How to Diagnose and Troubleshoot

Diagnosis of B1435 requires a systematic approach, utilizing a digital multimeter (DMM) and an OBD-II scan tool, coupled with a thorough visual inspection and knowledge of the vehicle’s specific wiring diagrams.

1. Visual Inspection:
   • Begin by visually inspecting the wiper high/low speed relay, its socket, and the surrounding wiring harness for any obvious signs of damage, corrosion, melting, or loose connections. Pay close attention to the fuse panel where the relay is located, checking for water ingress or debris.
   • Locate and inspect all fuses related to the wiper system. While a blown fuse doesn’t always directly cause an “open coil circuit” code, it can lead to a lack of power to the coil, which the module might interpret as an open.
2. Scan Tool Data Analysis:
   • Connect an OBD-II scan tool and confirm the presence of code B1435. Check for any other related diagnostic trouble codes (DTCs) that might indicate a broader electrical issue.
   • If the scan tool supports it, access BCM/IPM live data to monitor the status of the wiper switch inputs and the command status for the wiper relays. This can help confirm if the control module is attempting to activate the relay.
3. Wiper Relay Testing:
   • Identify and carefully remove the specific wiper high/low speed relay from its socket (refer to vehicle service manual for location and identification).
   • Using a DMM, measure the resistance across the relay coil terminals (typically pins 85 and 86). A functional relay coil should exhibit a measurable, low resistance (e.g., 50-150 ohms). An “OL” or infinite resistance reading indicates an open circuit within the relay coil itself.
   • To further test, apply 12V power and ground to the relay coil terminals (again, referencing the relay pinout diagram). Listen for an audible click, indicating the coil is energizing and switching the internal contacts. Then, use the DMM to check for continuity across the switch contacts (typically pins 30 and 87/87a).
   • Alternatively, swap the suspected faulty relay with a known good, identical relay from a non-critical circuit (e.g., horn relay, if compatible) and retest the wiper functionality.
4. Circuit Continuity and Voltage Testing:
   • With the relay removed and the ignition off, use the vehicle’s wiring diagrams to identify the power supply and ground control terminals for the wiper relay coil circuit at the relay socket.
   • Power Supply Check: With the ignition ON, use a DMM to check for appropriate voltage at the power supply terminal of the relay coil socket. If no voltage, trace back to the fuse or power distribution module.
   • Ground/Control Circuit Check: With the ignition OFF, test for continuity between the control module’s relay driver output terminal (at the module connector, if safely accessible) and the corresponding relay socket terminal. An open circuit here indicates a wiring issue.
   • Load Test (Optional): If basic continuity checks pass, consider performing a voltage drop test on the power and ground circuits to identify high resistance points that may not show as a complete open with a simple continuity test but prevent proper current flow.

Recommended Repairs and Solutions

Once the diagnostic steps have pinpointed the root cause of B1435, the following repairs are typically recommended:

• Replace the Faulty Wiper Hi/Low Speed Relay: If the relay coil tested open or the relay failed functional testing, replacement with a new, OEM-specification relay is the most common and effective solution. Ensure the replacement relay matches the original in terms of part number and specifications.
• Repair or Replace Damaged Wiring: If an open circuit is identified in the wiring harness, the damaged section must be repaired. This involves carefully cutting out the compromised wire segment, soldering in a new section of the correct gauge wire, and sealing the repair with heat-shrink tubing to prevent future corrosion or damage. If the damage is extensive or involves multiple wires, replacing the entire harness section may be more practical.
• Clean and Secure Relay Socket Connections: If corrosion, dirt, or loose pin tension is found within the relay socket, clean the terminals thoroughly using a specialized electrical contact cleaner and a small brush. Carefully use a pick or small screwdriver to gently adjust the female terminals to ensure proper tension and secure connection with the relay pins.
• Replace Blown Fuse: If a fuse was found to be blown, replace it with a new fuse of the correct amperage. It is crucial to investigate why the fuse blew, as it might indicate an underlying short circuit elsewhere in the wiper system, which should be addressed to prevent the new fuse from blowing again.
• Replace the Body Control Module (BCM)/Integrated Power Module (IPM): If all other components (relay, wiring, fuses) have been thoroughly tested and confirmed to be in good working order, and the control module’s relay driver output is demonstrably faulty (e.g., no voltage or ground command when expected), then replacement of the BCM/IPM may be necessary. It is important to note that control module replacement often requires specialized programming or configuration to the vehicle using a compatible scan tool after installation.

After any repair, clear the DTCs with a scan tool and perform multiple functional tests of the wiper system through all modes (intermittent, low, high) to ensure the repair is successful and the code does not return.