Wipers and washers: the faults you can fix yourself

Wipers are a system where repair costs differ by an order of magnitude depending on cause, while the symptom is often identical. So a few minutes spent separating causes pays directly.

Nothing works at all

The fuse. The first thing to check and the cause in a noticeable share of cases. What matters is not just replacing it but understanding why it blew: an overloaded motor from blades frozen to the glass is the classic story; covered in the fuses article.

The stalk switch. The sign is one mode working and another not — intermittent works, continuous does not.

The wiper motor. The most expensive hypothesis, which is exactly why it is checked last.

A simple test: switch the wipers on and put a hand on the motor housing. Vibration or humming with no blade movement means the motor is alive and the fault is mechanical.

The motor hums, the blades stay put

A classic, and the cause is almost always the same.

Worn linkage splines. The shaft turns and the arm on it slips. The repair is usually cheap: tighten or replace the nut and splined joint.

A seized linkage. The bushes have corroded and the mechanism will not move. Then the motor overloads — and blows the fuse the story started with.

The most common cause of both is switching the wipers on against a frozen screen.

The blades move incorrectly

They will not park in the lower position — a faulty park position sensor in the motor.

They ride onto the bodywork or stop short — misadjusted arms, usually after removal or an impact.

They hit each other — the same cause.

They leave streaks — that is the blade rubber, not the mechanism.

The washer will not spray

In winter — usually frozen fluid in the reservoir, hoses, or jets. The pump either hums or stays silent, depending on its protection.

In summer — blocked jets. Clear them gently with a fine needle so the orifice is not enlarged.

The pump does not hum — the fuse or the pump itself.

It hums but does not spray — a hose has come off or split. The typical spot is under the bonnet near the hinges.

The fluid disappears — a cracked reservoir. In winter that follows water freezing inside.

The main rule: do not fill it with water instead of washer fluid. One frost and the reservoir and pump become an expense rather than a saving.

What diagnostics can show

Wipers are mostly electromechanical, but on modern cars they are connected to the body module as well.

Body electronics codes — for the wiper circuit and the washer pump.

The rain sensor — on cars with automatic mode it lives on the windscreen. After a screen replacement it is frequently refitted incorrectly, and the wipers either ignore rain or run without it. That shows as a code or as a light parameter in live data.

Washer fluid level — a parameter showing whether the reservoir float works.

What to do before winter

1. Fill washer fluid rated for the temperature, not “minus five just in case”.
2. Lift the blades or free them from snow before switching on.
3. Never run the wipers on ice — the main cause of everything in this article.
4. Replace the blade rubber if it is a year old or more.
5. Clear the jets before the frosts, not after.

In short

• Humming without movement means mechanics, not the motor.
• Worn linkage splines are the most common and cheapest cause.
• A blown fuse has a reason: usually blades frozen to the glass.
• Water instead of washer fluid costs a reservoir and a pump.
• A rain sensor is often refitted wrongly after a screen replacement.

Download the app — body electronics codes are read with an ELM327 adapter over Bluetooth SPP on Android.