Tail Lights: Guides by Make & Model

Multiple functions in one housing means one fault can mean several different things. Find your specific model below.

More Wiring Than You'd Expect

Brake light, indicator, reversing light and rear fog light often share one unit. Pick your make and model below for the specifics.

Any Non-Functioning Light Is an Automatic MOT Failure

There's no grey area here: a blown bulb in any tail light function — position light, brake light, indicator, reversing light, or rear fog light — is treated as a major defect and an automatic MOT failure, regardless of how minor it might seem. It's genuinely worth checking every function before your test date; a five-minute walk-around with a second person pressing the brake pedal and cycling the indicators catches problems that are easy to miss from the driver's seat alone.

Halogen, LED, or a Mix — and Why Upgrading Isn't as Simple as It Looks

Rear light clusters use the same basic bulb technologies as headlights — halogen filament bulbs, and increasingly LEDs, either as replaceable bulbs or as sealed units built into the housing itself. It's worth knowing that the UK's strict rules against converting halogen headlamp housings to LED bulbs (a definite MOT failure under the current inspection manual) are specifically about headlamps, not rear lights — there's no equivalent blanket ban currently written into the MOT manual for brake lights, tail lights, or reversing lights. That said, any replacement bulb still needs to be correctly E-marked and rated for the correct wattage — UK/EU legislation specifies exact electrical and photometric requirements even for something as simple as a stop lamp bulb, so an uncertified bulb bought purely on the promise of looking brighter can still leave you with an MOT advisory or failure for inadequate light output, incorrect colour, or an unapproved fitting.

If your car came from the factory with a sealed LED tail light unit, the whole assembly is generally replaced as one part rather than a serviceable bulb — there's no bulb-swap option, which is one reason genuine or correctly-specified aftermarket LED tail light housings tend to cost meaningfully more than an equivalent halogen unit with a simple bulb holder.

One Housing, Several Circuits — Which Makes Diagnosis Trickier Than It Looks

A single rear light housing commonly carries the position (sidelight), brake, indicator, reversing, and — on many European-spec cars — rear fog light functions all in one unit, each on its own separate bulb and wiring circuit even though they share one physical housing. This matters diagnostically: if only one function has stopped working, the fault is very likely that specific bulb or its individual wiring, not the whole unit. But if multiple functions on the same side have failed simultaneously, that's a stronger sign of a shared problem — a corroded earth connection, a failed multi-pin connector at the back of the housing, or water ingress into the unit itself, which is a surprisingly common failure mode on older cars where the housing seal has degraded and let moisture track along the wiring loom.

Genuine water ingress is worth taking seriously beyond just the electrical fault it causes — condensation visible inside the lens, or a housing that looks like it's been steamed up from the inside, points to a failed seal that will keep causing repeat bulb and connector failures until the housing itself is replaced, not just the bulb currently blown.