Is a cracked tail light cover an MOT failure?

A cracked tail light cover is an MOT failure if it exposes the bulb, allows water ingress, changes the light colour (e.g., white light showing through a red lens), or significantly reduces light output. An advisory is issued for minor damage.

Can I use sealant on a cracked tail light lens?

Clear automotive sealant provides a temporary fix to prevent water ingress in a hairline crack, but it does not restore structural integrity. Plan for replacement at the earliest opportunity.

What causes tail light lenses to yellow?

UV radiation breaks down the polycarbonate material, causing surface oxidation. Heat cycling from the bulbs and road grit abrasion accelerate the process. Parking outdoors in direct sunlight speeds deterioration.

Are aftermarket tail light covers safe?

Quality aftermarket covers that are e-marked (homologated) meet the same light transmission and durability standards as OEM parts. Unbranded or non-e-marked covers may not comply with lighting regulations.

Do I need to reprogram anything when replacing a tail light cover?

On a basic bulb-type assembly, no — replacement is plug-and-play. LED units with a CAN bus interface may require coding to prevent a bulb failure warning. Check whether your vehicle requires this step.