Under-cabinet lighting not working

Symptoms

• Entire under-cabinet light run is dark
• One section works while another doesn't
• Lights flicker or dim unexpectedly

Likely causes

• CommonA failed or unplugged low-voltage transformer/driverMost under-cabinet LED strips or pucks run on a separate power supply that can fail independently.
• CommonA loose connector between sectionsLinkable LED strip sections rely on small connectors that can loosen or corrode.
• PossibleA tripped breaker or switch for that circuitWorth checking if the whole run, including the transformer's indicator light, is dark.
• PossibleA damaged section of LED strip or wiringPhysical damage, like from a dropped object, can cut power to sections beyond that point.

What to do

1. Check the transformer or driver, often inside a cabinet, for a power indicator light.
2. Confirm the transformer is plugged in or wired in and hasn't tripped its own protection.
3. Check the breaker panel and wall switch controlling that circuit.
4. Inspect connectors between light sections for looseness or corrosion.
5. Reseat any loose connectors, with power off if they're hardwired rather than plug-in.
6. Replace the transformer/driver if it shows no power output despite having power at its input.
7. Call an electrician if the transformer is hardwired and needs replacing, or wiring inside the cabinet looks damaged.

Tools and parts

• Screwdriver
• Non-contact voltage tester

When to call a pro

Call an electrician if the transformer is hardwired and needs replacement, or if wiring inside the cabinetry is damaged.

Safety