B1585 – Dim Panel Decrease Input Circuit Short To Battery

The ODBII code B1585 indicates a short circuit in the dim panel decrease input circuit, which is causing it to receive a constant voltage from the battery instead of the expected variable signal.

The severity of ODBII code B1585 is moderate.

Common Causes For: B1584 Dim Panel Decrease Input Circuit Open

• Shorted wiring or connectors
• Faulty dimmer switch
• Malfunctioning instrument cluster
• Corroded or damaged electrical connections
• Faulty body control module (BCM)
• Grounding issues
• Incorrectly installed aftermarket accessories

Common misdiagnosis for B1585 Dim Panel Decrease Input Circuit Short To Battery

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

Common Troubleshooting Steps

The OBD-II code B1585 indicates a problem with the “Dim Panel Decrease Input Circuit,” specifically a short to battery. This code is often related to the vehicle’s dashboard lighting or dimming controls. Here are some common troubleshooting steps to diagnose and resolve the issue:

• Check the Vehicle’s Wiring:: Inspect the wiring harness and connectors associated with the dimming circuit for any signs of damage, fraying, or corrosion.
• Look for any exposed wires that may be shorting to the battery or other circuits.
• Inspect the Dimmer Switch:: Test the dimmer switch for proper operation. A faulty switch can cause incorrect signals to be sent to the control module.
• If possible, use a multimeter to check for continuity and resistance in the switch.
• Check for Short Circuits:: Use a multimeter to check for continuity between the dimming circuit and the battery voltage. A short circuit will show continuity where it shouldn’t.
• Disconnect the battery and check the circuit for shorts to ground or battery voltage.
• Examine the Instrument Cluster:: If the vehicle has an integrated instrument cluster, check for any faults within the cluster itself.
• Look for any signs of water intrusion or damage that could affect the circuit.
• Scan for Additional Codes:: Use an OBD-II scanner to check for any other related trouble codes that may provide additional context for the issue.
• Address any other codes that may be present, as they could be related.
• Inspect Fuses and Relays:: Check the fuses related to the dashboard lighting and dimming functions. Replace any blown fuses.
• Inspect any relays that may be involved in the dimming circuit.
• Test the Control Module:: If all other components check out, the issue may lie within the vehicle’s control module. Testing or reprogramming the module may be necessary.
• Consult the vehicle’s service manual for specific testing procedures for the control module.
• Clear the Code and Test Drive:: After performing repairs, clear the trouble code using an OBD-II scanner.
• Take the vehicle for a test drive to see if the code reappears.
• Consult a Professional:: If the issue persists after performing these steps, it may be best to consult a professional mechanic or technician who has experience with your specific vehicle make and model.Additional Tips: – Always disconnect the battery before working on electrical components to avoid shorts or shocks. – Refer to the vehicle’s service manual for specific wiring diagrams and troubleshooting procedures related to the dimming circuit. By following these steps, you should be able to identify and resolve the issue related to the B1585 code.