Why are my landscape lights not working?

The most common cause is loss of power at the transformer, timer, or photocell

Start at the transformer, because every low-voltage landscape lighting system depends on it. Most residential systems take 120V power from an outdoor GFCI-protected receptacle and step it down to 12V or 24V for the yard fixtures. If the transformer is dead, switched off, overloaded, or not receiving power, every light on that transformer will be out.

Check the simple items first:

• Is the transformer plugged in and switched on?
• Has the outdoor GFCI receptacle or upstream GFCI tripped?
• Is the breaker on, and is anything else on that circuit working?
• Is the timer set to the right time, AM/PM, day schedule, and mode?
• Is the photocell covered by leaves, dirt, mulch, snow, or a nearby light source?
• Is the transformer set to “auto” instead of “off” or “manual override”?

Photocells cause many confusing failures. A porch light, garage coach light, or even reflected light from a window can trick the photocell into thinking it is still daytime. The opposite can happen too: a dirty or shaded sensor may keep the lights on during the day. Astronomical timers avoid some of this, but only if the clock, location, and daylight-saving settings are correct.

If the transformer hums loudly, smells burnt, has a melted terminal block, or trips as soon as the low-voltage wires are connected, stop resetting it. That points to a short, overload, or internal failure. We troubleshoot outdoor lighting systems by separating the 120V supply, transformer output, low-voltage cable, and fixture zones so the failed part is not guessed at.

For 120V exterior equipment, the Ontario Electrical Safety Code expects outdoor wiring methods and weather protection suitable for wet locations. A plug-in transformer should not be sitting in a puddle, lying in mulch, or connected through a loose extension cord. If the receptacle itself is dead, see our related guide on outdoor outlets that stop working.

If only some fixtures are out, suspect damaged cable, corroded connectors, or a bad fixture

When half the lights work and half do not, the transformer is usually not the whole problem. A low-voltage landscape lighting run is a chain: transformer terminals, main cable, branch splices, fixture leads, lamps or LED modules, and the fixtures themselves. One bad splice can take out everything downstream.

Common outdoor failures include:

The connectors matter. Many older systems use “piercing” or “vampire” connectors that bite through the cable jacket. They are quick to install but can loosen, corrode, or fill with moisture over years of freeze-thaw cycles. Better repairs use outdoor-rated, gel-filled, burial-rated connectors sized for the actual cable and fixture leads.

Cable damage is also common near walkways, garden edging, trees, and irrigation work. Low-voltage cable is often only shallow-buried, so it can be cut without anyone realizing it. Sometimes the damage does not kill the lights immediately; water enters the jacket, copper turns black or green, and the voltage slowly becomes unstable.

Do not keep twisting bare copper together and wrapping it with tape. It may work for one evening, but wet soil will find it. Corroded joints create resistance, dim lights, intermittent operation, and heat at the splice. If the system shares a GFCI-protected outdoor receptacle and moisture is involved, it may also begin tripping; that is a different symptom covered in why outdoor lights keep tripping.

Dim lights at the end of the run usually mean voltage drop or an overloaded layout

If the lights closest to the transformer are bright but the last ones are weak, orange, flickering, or unreliable, voltage drop is the likely issue. Low-voltage lighting uses thicker cable and shorter runs for a reason: the farther the current travels, the more voltage is lost in the wire. Add too many fixtures on one long run and the last fixtures may not receive enough voltage to operate properly.

This is especially noticeable on older halogen systems. A 12V halogen lamp that receives too little voltage looks yellow and may have a shortened life. LED fixtures draw less current, so they are more tolerant, but they still need voltage within the driver’s operating range. If the voltage at the transformer is fine but the far fixture is low, the problem is the layout, cable size, connections, load, or run length.

We test voltage under load, not just with the fixtures disconnected. A cable can show acceptable voltage with no load, then collapse when all fixtures turn on. We also compare readings at:

• The transformer secondary terminals
• The first fixture on the run
• Major splice points
• The last fixture on each branch
• Any zone that behaves differently from the rest

A better layout may use multiple cable runs from the transformer instead of one long daisy chain. Sometimes the fix is moving loads to a second tap on a multi-tap transformer, upsizing the low-voltage cable, splitting zones, or replacing a transformer that is too small for the connected wattage.

Transformer capacity is not just the number printed on the box. You have to add the actual load of every fixture on that transformer and leave room for voltage stability and future additions. If someone swapped in higher-wattage lamps, added path lights, or connected backyard fixtures to a front-yard transformer, the system may now be overloaded even though it used to work.

Repeated failures often mean the system should be redesigned with LED fixtures, not patched again

If you are replacing lamps, splices, sockets, or transformers every season, the system may be past the point where small repairs make sense. Replacement with LED fixtures can solve repeated failures when the old system is overloaded, heat-damaged, poorly connected, or built around deteriorating halogen fixtures.

LED landscape lighting helps because it reduces total wattage on the transformer and cable. Lower current means less voltage drop, less stress on splices, and more flexibility in fixture placement. It can also allow a smaller or better-zoned transformer setup, especially when an old halogen system was built right at the edge of capacity.

Replacement makes sense when we see several of these at once:

• Old halogen fixtures with corroded sockets
• Burnt or brittle fixture leads
• Many taped splices or mismatched connector types
• Transformer terminals showing heat damage
• Long daisy-chain runs with dim far-end lights
• Fixtures buried by mulch, soil, or plant growth
• No clear zoning between front yard, side path, and backyard

A front-yard low-voltage landscape lighting package, including transformer, wiring, and 6–10 fixtures, usually starts in the $1,500–$3,000 range and scales with property size, fixture grade, and trenching or fishing difficulty. Repair work is quoted in writing after a site visit because the time depends on how accessible the cable and splices are.

LED replacement does not mean every fixture must be bright white. A good outdoor system should use the right colour temperature, beam spread, glare control, and fixture spacing. Path lights, uplights, step lights, and wall-wash fixtures do different jobs. The electrical work is only half the result; the layout determines whether the yard feels safe and finished or patchy and over-lit.

If the lighting is part of a broader exterior plan, we also look at outdoor receptacles, switching, smart controls, and whether a dedicated circuit is needed for heavier exterior loads. For small device issues inside the home, our outlet troubleshooting guide explains a different set of symptoms.

Call an electrician when the fault involves 120V power, repeated transformer failure, or buried cable tracing

You can safely check settings, clean a photocell, reset a GFCI once, and replace a listed low-voltage lamp if the fixture is designed for it. Call a licensed electrical contractor when the issue keeps returning, affects the 120V supply, involves wet equipment, or requires cutting and splicing buried cable.

A proper service call should identify the failure rather than simply replacing parts. For landscape lighting, that usually means:

• Confirming the outdoor receptacle, GFCI protection, and weatherproof cover
• Testing transformer input and low-voltage output
• Checking timer, photocell, and control programming
• Measuring voltage at the start and end of each run
• Opening suspect splices and checking for corrosion
• Tracing buried cable where damage is likely
• Verifying fixture load against transformer capacity
• Recommending repair, rezoning, or LED replacement based on the actual fault

New hardwired outdoor electrical work may require an ESA notification and inspection. City Power Electrical Services is an ECRA/ESA Licensed Electrical Contractor, #7015314, and when an ESA notification is required we include that step in the written scope rather than leaving it as an afterthought.

If the lights turn on at odd times but otherwise work, the problem may be a control or sensing issue; see why lights turn on by themselves. If the whole system is dead, dim, corroded, or unreliable after rain, book an outdoor lighting diagnosis and get the repair or replacement path in writing.