B1586 – Dim Panel Decrease Input Circuit Short To Ground

The ODBII code B1586 indicates a short circuit in the dim panel decrease input circuit, which affects the vehicle’s ability to adjust the brightness of the dashboard lights.

The severity of ODBII code B1586 is moderate.

Common Causes For: B1585 Dim Panel Decrease Input Circuit Short To Battery

• Shorted wiring or connectors
• Faulty dimmer switch
• Grounding issues
• Damaged or corroded connectors
• Malfunctioning body control module (BCM)
• Faulty instrument cluster
• Incorrectly installed aftermarket accessories

Common misdiagnosis for B1586 Dim Panel Decrease Input Circuit Short To Ground

• Faulty dimmer switch
• Shorted wiring harness
• Defective instrument cluster
• Malfunctioning body control module (BCM)
• Bad ground connections
• Incorrectly installed aftermarket accessories
• Faulty headlight switch

Common Troubleshooting Steps

The OBD-II code B1586 refers to a problem with the “Dim Panel Decrease Input Circuit,” indicating that there is a short to ground in the circuit responsible for dimming the instrument panel lights. Here are some common troubleshooting steps to diagnose and resolve this issue:

• Check the Vehicle’s Manual: Refer to the vehicle’s service manual for specific information about the dim panel decrease input circuit, including wiring diagrams and component locations.
• Visual Inspection: Inspect the wiring and connectors associated with the dimming circuit for any visible damage, such as frayed wires, corrosion, or loose connections.
• Look for any signs of wear or damage in the harness that could lead to a short to ground.
• Check Fuses: Inspect the fuses related to the instrument panel and dimming circuit. Replace any blown fuses and check if the code reappears.
• Test the Dimmer Switch: The dimmer switch itself may be faulty. Test the switch for proper operation using a multimeter. Check for continuity and ensure it is functioning as intended.
• Check for Shorts to Ground: Use a multimeter to check for continuity between the dimming circuit wire and ground. If there is continuity, there is likely a short to ground somewhere in the circuit.
• Trace the wiring back to find the source of the short. Look for pinched wires, damaged insulation, or improper routing.
• Inspect Related Components: Check other components that may be connected to the dimming circuit, such as the body control module (BCM) or any relays. Ensure they are functioning correctly.
• Scan for Additional Codes: Use an OBD-II scanner to check for any additional trouble codes that may provide more context or indicate related issues.
• Clear the Code: After performing repairs, clear the trouble code using an OBD-II scanner and take the vehicle for a test drive to see if the code returns.
• Consult a Professional: If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or technician who has experience with electrical systems and can perform more advanced diagnostics.
• Document Findings: Keep a record of any findings, repairs made, and codes that were present. This documentation can be helpful for future reference or if further assistance is needed. By following these steps, you should be able to identify and resolve the issue related to the B1586 code. Always ensure safety precautions are taken when working with electrical systems in vehicles.