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DTC codes / B02xx · Airbags, seats, doors, lights and comfort systems / B0260

B0260Interior Light Circuit

B0260 is a body code indicating a fault in the interior light circuit, which typically includes the dome light, courtesy lamps, and their associated wiring and switches. The body control module (BCM) monitors this circuit and sets the code when it detects an unexpected voltage condition, such as an open circuit, short to ground, or short to power, often confirmed by comparing commanded state to actual feedback.

SystemBody
Code typeGeneric (all makes)
SeverityLow
Fix difficultyIntermediate
AreaAirbags, seats, doors, lights and comfort systems

Symptoms you may notice

  • Interior lights fail to turn on when a door is opened or the switch is activated
  • Interior lights stay on continuously, even with all doors closed and the switch off
  • One or more interior lamps do not illuminate while others work normally
  • The warning light on the dashboard may be the only sign, with no noticeable lighting issue
  • Battery drains overnight due to a lamp remaining powered
  • Flickering or intermittent operation of interior lights over bumps

Common causes, most likely first

  1. Failed bulb or LED assembly in one of the interior lamps
  2. Corroded or disconnected ground connection for the interior light circuit
  3. Broken, chafed, or pinched wire in the interior light harness, often at door jambs or hinges
  4. Faulty door jamb switch or courtesy lamp switch that stays open or closed
  5. Defective body control module (BCM) output driver for the interior light circuit
  6. Blown fuse or poor connection at the fuse box for the interior lighting circuit
  7. Water intrusion into a lamp housing or connector causing a short

How to diagnose and fix it

  1. Verify the fault by checking all interior lamps with doors open and closed, and note any that are inoperative or stay on
  2. Inspect and test the fuse for the interior light circuit, replacing it only if blown and investigating why
  3. Check the bulb or LED assembly in each affected lamp, replacing any that are failed
  4. Measure voltage and ground at each lamp connector with the circuit commanded on and off to isolate an open or short
  5. Inspect wiring and connectors at door jambs, hinges, and under trim panels for chafing, corrosion, or looseness
  6. Test the door jamb switches and the interior light switch for proper continuity in each position
  7. If all inputs and wiring are good, test the BCM output with a scan tool and a load, and replace or reprogram the BCM only after confirming a faulty driver

Interior light faults that fool technicians

  • A common oversight is replacing the BCM when the real problem is a chafed wire in the door jamb boot, which flexes with every door open and close and eventually shorts to ground.
  • The BCM may set B0260 even when the interior lights work normally, because the code can be triggered by a brief glitch during battery replacement or low voltage, so always check for history codes and clear them before condemning parts.
  • Aftermarket LED bulbs can draw too little current for the BCM's circuit monitoring, causing it to set a false B0260 even though the lights function; restoring incandescent bulbs or adding a load resistor often resolves it.
  • A faulty door ajar switch can keep the interior lights on and drain the battery, yet the switch may test fine with a multimeter because the fault is intermittent and only appears with vibration or temperature change.
  • Water leaking past a rear lamp gasket or sunroof drain can corrode the interior light connector and create a short that sets B0260, so always inspect for moisture stains and corrosion inside lamp housings.

Can I keep driving with B0260?

The vehicle remains safe to drive because interior lighting does not affect engine, steering, or braking, but address a lamp that stays on to avoid a dead battery. Avoid parking in isolated areas if the interior lights are inoperative at night, and fix any short circuit promptly to prevent further electrical damage.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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