Interior Light Control Module (ILCM) Circuit Low
There’s an issue with the low voltage circuit in the interior light control module.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The interior lights rely on a control module that uses a low voltage circuit to turn on and off. When this circuit isn’t functioning properly, the lights may not work as intended, indicating a possible wiring issue or module failure.
What the computer is actually seeing
The interior light control module detects low voltage (below 2 volts) in the signal circuit when it expects a higher voltage (around 5 volts or more) during operation.
What a healthy reading looks like
Voltage in the low circuit should be between 5 to 12 volts when the lights are supposed to be on.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Inspect the interior light circuit harness and connectors for any damage or corrosion. Repair as necessary. Decision Point: Are there any visible issues? Yes—fix and retest. No—continue to step 2.
- 22. Measure the voltage at the interior light control module connector with the lights turned on. Expected: 5 to 12 volts. Decision Point: Is the voltage within range? Yes—module may be faulty. No—continue to step 3.
- 33. Check the wiring between the control module and the interior lights for continuity and shorts to ground. Repair any issues found. Decision Point: Are all wires intact? Yes—module likely bad. No—fix wiring and retest.
Common causes
- Loose or corroded connectors
- Faulty interior light control module
- Damaged wiring harness or short circuit
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
Yes, but the interior lights may not work correctly, affecting visibility at night.
Will this code come back after clearing?
It can come back if the underlying issue isn’t resolved, particularly with wiring or the module.
Why does this relate to the lights and the control module?
The control module manages the operation of the interior lights, and low voltage signals indicate a circuit issue.
Working a real vehicle right now?
Let DiagCoach walk you through it live with your specific symptoms, vehicle, and what you've already checked.
Start guided diagnostic →