Electrical & Lighting

BuildingWrench repair guide

Outdoor Light Won’t Turn On at Night: Photocell and Timer Checks

Exterior lighting that stays off at night may be controlled by a photocell, astronomical timer, BAS schedule, contactor, breaker, or fixture driver. Identify the control method first.

Last reviewed 2026-09-12 · General facility-maintenance information, not a substitute for site procedures, manufacturer instructions, codes, or qualified professional judgment.

Safe first checksSkill: Beginner-friendlyFormat: Diagnose → Fix → Test

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Safety boundary

This guide stops before energized wiring or panel work. Use qualified electrical personnel for internal diagnosis.

Full troubleshooting steps are in Pro

The safety boundary, quick answer and stop-work conditions above stay free. Pro opens the likely causes, symptom table, step-by-step procedure and preventive maintenance for this guide.

Stop and call a licensed professional when

Panel or contactor wiring diagnosis is required
Multiple safety or security areas are dark
Fixture is overheated or damaged

Mistakes, FAQ, parts and tools

Pro opens the rest of this guide: common mistakes, field FAQ, the parts list, and the tools for the job.

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Occupancy Sensor Light Won’t Turn Off: Easy Checks Before Replacement

Lights that stay on with an occupancy sensor are often caused by a long time delay, sensitivity settings, air movement, moving objects, line-of-sight traffic, or an override mode. Start with settings and the room before replacing the sensor.

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Emergency Light Battery Won’t Hold a Charge? What to Check

If an emergency light fails its required test duration, first verify that normal power and charging are present. An aged battery is common, but charger faults, lamp problems, or loss of normal-power sensing can produce similar symptoms.

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Lighting Problem: Flicker, Outage, and Controls

Count the fixtures. One fixture out is usually a lamp, driver, or ballast. A whole row or zone out is a circuit or control problem. Flicker after an LED retrofit usually means a driver or dimmer compatibility issue. Fixture wiring and ballast replacement is qualified work in most sites.

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GFCI Won’t Reset? Safe Checks Before Replacing the Receptacle

A GFCI that will not reset is not automatically bad. Unplug connected equipment, check for moisture, verify upstream protection, and try one firm reset. If it trips again or shows heat, odor, or damage, take it out of service and escalate.