A crack through the lens usually means replacing the whole assembly
On a modern car the headlight is a sealed unit. The clear lens is polycarbonate, bonded to the housing behind it with a permanent adhesive, and the bulbs or LED modules, reflectors and wiring sit inside. Once the lens cracks through, that seal is broken. Unlike a windshield chip, there is no reliable resin repair for a structural crack in a headlight lens, and the lens is not sold separately for most vehicles.
A cracked lens also changes the light. The crack scatters the beam, which can throw glare at oncoming drivers and leave a dimmer patch on the road ahead. On a dark January evening on the 404 north of Major Mackenzie, with slush on the road, that matters. A lamp with a damaged lens can also be flagged when a used vehicle goes for its Safety Standards Certificate, so if you plan to sell, budget for the replacement.
A fine surface scratch or crazing in the outer hard coat is a separate issue and not a crack. That kind of damage, along with yellowing and fog, is often something a lens restoration can improve.
Broken mounting tabs are the part of a headlight that can often be saved
Many headlights damaged in a corner hit are fine at the front and broken at the back. The housing is held to the car by a few plastic tabs with bolt holes, and a bumper pushed rearward snaps them. The lamp then sits loose, rattles or points the wrong way, even though the lens is perfect.
Tabs are repairable more often than people expect. Some manufacturers sell tab repair kits for specific lamps: a replacement tab that bonds or screws onto the housing in place of the broken one. Where no kit exists, a technician can often rebuild a tab by plastic welding with a reinforcing mesh. Either way, the repaired tab has to hold the lamp firmly enough to keep it aimed over potholes and expansion joints, so if the break runs into the main housing near the bulb or the lens seal, replacement is the safer call.
- Lens cracked or holed through: replace the assembly.
- One or two tabs snapped, lens intact: tab kit or plastic weld, then aim.
- Housing cracked near the bulb or the lens seal: replace.
- Lens hazy, yellow or lightly scratched: restoration may be enough.
Water inside the lamp means the seal has failed somewhere
A thin film of condensation that forms on a cold morning and clears after a few minutes of driving is often normal; headlights breathe through small vents. Droplets that stay, or a puddle sitting in the bottom of the housing, mean water is getting in. After a collision that is usually a hairline crack you cannot see, a broken tab that let the housing flex, or a vent cap knocked off.
Water does not stay harmless. It fogs the lens from inside, corrodes bulb sockets and connectors, and can damage the electronics that drive LED units. Road salt spray in a GTA February makes it worse. Driving through a car wash with a cracked housing is a quick way to find out how much water it lets in. If moisture appeared after a hit, have the lamp checked before it becomes an electrical fault rather than a cosmetic one.
LED, HID and adaptive lamps shift the repair-or-replace decision
On an older car with a halogen bulb, a headlight assembly is a fairly simple part. On newer cars it may contain sealed LED modules that are not serviceable on their own, levelling motors, a control unit, and on some models adaptive functions that swivel the beam into corners or shade out oncoming cars. Those assemblies are expensive, which makes saving a lamp with only broken tabs far more worthwhile.
When an assembly does have to be replaced, the source matters. A new OEM lamp, a recycled OEM lamp and an aftermarket copy can all appear on an estimate. Aftermarket lamps vary in fit and beam pattern, and on a car with adaptive lighting a replacement may need to be set up with a scan tool before every function works. Some vehicles also mount a camera or sensor near the headlight, and work in that area may require a calibration check afterward.
Every headlight that goes back on the car should be aimed
Whether the lamp was repaired or replaced, the job is not finished until the beam is aimed. A small shift in the mounting point, or a fender support that was bent in the hit, can point a perfectly good headlight into the eyes of oncoming traffic or at the ditch. Aiming is checked against a target at the correct height and distance, with each lamp adjusted until the cut-off line sits where it belongs.
If the headlight was damaged in a collision, it goes on the claim with the rest of the corner and the aim is part of that repair. If it cracked on its own or from a stone on the 401, the coverage question is different, which the FAQ below covers.
Questions people ask
Is a headlight cracked by a stone on the highway covered by insurance?
That depends on your policy and on how your insurance company classifies the damage, so ask them before assuming. A headlight broken in a collision is claimed with the rest of that damage. Whatever the coverage, compare your deductible with the repair estimate first.
Can clear tape or silicone keep a cracked headlight going until spring?
Tape can slow water entry for a short time, but it does not restore the seal or fix the scattered beam, and silicone on the lens can make a later repair harder. Treat either as a stopgap of days, not months.
If one headlight is replaced, will it look different from the other side?
A new lens is often clearer than an older one that has yellowed. Many owners restore the older lens at the same visit so the two match. Nothing requires you to replace both.
My headlight is loose but not cracked. Is it safe to drive?
For a short trip in daylight, usually. A loose lamp moves its beam over bumps, and broken tabs can let it fall further. Have the tabs repaired and the aim checked before relying on it at night.