The wiper isn't clearing the screen properly. That covers a perished or split blade, a torn rubber, a blade that's lifting off the glass, or a wiper motor that isn't sweeping the full pattern.
Wording as it commonly appears on an MOT certificate: “Wiper blade defective or does not clear the windscreen effectively”.
What does it mean?
The wiper isn't clearing the screen properly. That covers a perished or split blade, a torn rubber, a blade that's lifting off the glass, or a wiper motor that isn't sweeping the full pattern.
How serious is it?
Usually recorded as: Major. The tester assesses the actual vehicle on the day, so your certificate is what counts.
What normally causes it?
- Perished rubber — blades harden with UV and frost and are usually done inside a year or two
- Blades torn by being frozen to the screen and switched on
- A weak wiper arm spring not pressing the blade down
- A worn wiper linkage causing a reduced or juddery sweep
What a mechanic would check
Wet the screen and watch a full sweep — smearing at the same point every time is the blade, a sweep that doesn't reach the top of the pattern is arm or linkage. I'd also check the washers work and are aimed at the screen, since they're tested together.
What might need replacing
- Wiper blades
- A wiper arm
- Linkage or motor, if the sweep pattern is short
Can you still drive it?
It's a failure and one of the easiest to sort yourself before a retest. New blades take five minutes and cost very little.
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This is general guidance from a UK mechanic, not a substitute for a physical inspection. Only the tester who inspected your vehicle can confirm what was recorded and why.