Indicator light inside box lit Emergency

Baxi Indicator light inside box lit Fault Code

Also written as INDICATORLIGHTINSIDEBOXLIT — same fault.

The Baxi Indicator light inside box lit fault code means: your boiler has detected that the electrical wiring coming into the unit is connected the wrong way around, which is a safety risk.. It appears on 2 Baxi models in our database.

Act immediately

Turn off your boiler and stop using gas appliances. Call a Gas Safe engineer now. This fault can be dangerous if ignored.

Technical description: Indicates that the live and neutral electrical connections are reversed.
Typical repair cost £90-160 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Baxi models that show the Indicator light inside box lit fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Baxi Indicator light inside box lit fault code information on this page is sourced and cross-checked against the official Baxi service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026