Windshield wipers are simple — but when they fail or leave streaks they become a safety hazard. This article explains every common cause (mechanical, electrical, and blade-related), how to diagnose the problem, step-by-step DIY checks, what a workshop will test, common repairs, urgency, maintenance tips, and quick copy-paste notes you can give a mechanic. Ready to paste into your blog.
Quick summary
Wiper problems usually fall into two groups:
- Wipers don’t operate at all or operate intermittently — electrical faults, blown fuse, bad motor, linkage failure, switch problems.
- Wipers operate but leave streaks, chatter, smear, or skip — worn blades, hardened rubber, dirty glass, bent arms, incorrect blade type, low washer fluid or clogged jets, or improper pressure from the arm spring.
Both reduce visibility in rain — fix promptly.
How the wiper system works (brief)
The wiper system consists of: wiper blades, wiper arms, mechanical linkage (transmission), wiper motor, park switch/park cam, wiper switch/relay, washer pump and nozzles, and sometimes a control module or rain sensor. The motor drives linkage that sweeps the blades; the park mechanism returns them neatly when turned off. Any failure in this chain causes the wipers to stop working or function poorly.
Detailed causes (why wipers stop or streak)
1. Worn or hardened wiper blades (most common cause of streaking)
- What happens: Rubber degrades from sunlight, heat and chemicals; edges harden or split.
- Effect: Blades don’t conform to the glass, they chatter, skip or smear water leaving streaks.
- Signs: Visible cracks, rough edges, tearing; streaks even after cleaning glass.
2. Dirty or contaminated blade/ windscreen
- What happens: Road grime, tree sap, oily deposits, or wax film prevent clean wiping.
- Effect: Blades smear instead of shear water, causing streaks and reduced contact.
- Signs: Smear persists after one wipe; glass looks hazy after wiping.
3. Incorrect or worn wiper arm tension / weak spring
- What happens: The arm spring that presses blade against glass weakens or the arm is bent.
- Effect: Poor contact especially on one edge — streaks or partial wiping.
- Signs: Blade lifts at speed or in corners; uneven contact along blade length.
4. Bent wiper arm or incorrect blade fitment
- What happens: Arm geometry wrong (hit by object or manually bent) or wrong blade type/size used.
- Effect: Edge misses glass or binding occurs causing skipping and streaking.
- Signs: Visual misalignment, blade edge not touching upper or lower part of screen.
5. Wiper blade bracket / spine or connector damage
- What happens: The metal spine, joints or adapter that hold rubber strip can be damaged/corroded.
- Effect: Uneven pressure and streaks; rubber may lift in spots.
- Signs: Flapping, uneven contact, parts of blade ride up.
6. Wiper motor failure or reduced torque
- What happens: Motor brushes wear, bearings seize or internal electrical faults reduce torque.
- Effect: Blades move slowly, stall under rain load, or stop intermittently.
- Signs: Sluggish sweep, whining from motor, no movement with electrical checks done.
7. Linkage or transmission problems (mechanical disconnect)
- What happens: Linkage joints wear, bushings fall out, or the arm splines slip; the motor spins but arms don’t move.
- Effect: Wipers don’t sweep, park or only twitch.
- Signs: Motor runs (you hear it) but blades stay parked or move irregularly.
8. Blown fuse, faulty relay, or wiring fault
- What happens: Electrical supply interrupted by a bad fuse, relay, or corroded connector.
- Effect: Wipers won’t turn on, work only at certain speeds, or stop working intermittently.
- Signs: No power at switch, multiple electrical symptoms, intermittent operation.
9. Faulty park switch/park cam or switch assembly
- What happens: Park switch inside motor or module fails — wipers don’t return to the rest position and may stall or stop mid-sweep.
- Effect: Wipers stop away from park position or don’t park correctly after switching off.
- Signs: Wipers stop in strange locations or won’t resume normal cycle.
10. Washer pump/nozzle issues (apparent streaks)
- What happens: Clogged or misaligned nozzles fail to wet glass evenly; low washer fluid or wrong fluid (silicone/oil contamination) leaves film.
- Effect: Wipers drag across an untreated film and smear.
- Signs: Nozzle spray pattern poor or blocked; fluid runs off without cleaning.
11. Damaged or delaminated windshield
- What happens: Old or pitted glass, or windshield with coating residue causes reduced contact.
- Effect: Even new blades streak on rough/pitted glass.
- Signs: Visible pitting under bright light; new blade fails to improve results.
12. Rain sensor or automatic wiper module faults (modern cars)
- What happens: Sensor misreads and gives incorrect on/off or intermittent commands, or control module fails.
- Effect: Erratic or non-functioning automatic wiping.
- Signs: Auto-wipe behaves oddly; manual wipe may still function but auto not.
Symptoms & what they point to
- Wipers don’t move but motor hums: linkage or splines slipped; mechanical disconnect.
- Wipers stop mid-sweep: park switch or module issue, or motor overload.
- Wipers leave streaks only at certain speeds: blade condition or arm pressure issue.
- Wipers chatter/skip across glass: hardened rubber, dirty glass, or incorrect blade type.
- Wipers fly up at high speed: weak arm spring or blade not properly seated.
- Washer fluid sprays but still streaks: dirty glass, wrong fluid, or low fluid pressure/nozzle misalignment.
- Complete no-op with no sound: blown fuse, disconnected wiring, bad switch.
Safe DIY checks (step-by-step)
Safety first: Park with engine off and ignition off when inspecting. Lift wiper arms gently — they are spring loaded and can snap back onto glass.
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Visual & tactile blade check
- Inspect rubber edge for cracks, splits, or glazing. Run a finger across the rubber — it should feel pliable, not hard or brittle. Replace if worn.
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Clean blades & windshield
- Use isopropyl alcohol or dedicated glass cleaner and a microfiber cloth to remove oil, wax or sap from glass and blades. Dirt is a major cause of streaks.
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Paper test for arm pressure
- Place a sheet of paper under the entire blade, close the arm gently and try to pull the paper out. If it slides out easily at some spots, spring pressure or blade contact is uneven.
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Check blade fitment & size
- Verify you have the correct blade type and length for your car. Adapter mismatch causes poor sealing.
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Inspect arm for bending
- Look at the arm profile — any twist or bend? If bent, it may be carefully reshaped or replaced.
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Operate wipers and listen
- Turn on the wipers and listen: a loud whine or grind suggests motor or linkage issue. If motor runs but blades don’t move, suspect linkage.
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Check washer jets & fluid
- Activate washer — jets should spray a broad, even pattern across swept area. Clean or replace clogged jets. Top up with proper washer fluid (not plain water, avoid oily additives).
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Check fuse & relay
- Locate fusebox and inspect wiper fuse/relay. Replace with correct rating or swap relay with a similar one to test.
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Check for play at the wiper pivot spline
- With arm lifted, wiggle the arm at the splined pivot — excessive play suggests worn splines or stripped splines.
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Test motor operation
- If safe, remove motor access panel and test motor directly (12V applied) — only if you know what you’re doing. Otherwise leave to a pro.
If cleaning and replacing blades solves the issue, great — otherwise proceed to professional checks.
Workshop diagnostics (what the mechanic will do)
- Visual & operational test: reproduce complaint, wet/dry tests at different speeds.
- Inspect linkage & splines: remove plastic cowl and check for worn joints, bushings, and stripped splines.
- Bench test wiper motor: check current draw, torque, brush condition, and park switch.
- Electrical trace: check fuses, relays, switch continuity, wiring and grounds with multimeter.
- Check washer pump & nozzle pressure: filtration and nozzle alignment.
- Rain sensor / module scan: read diagnostic trouble codes for auto-wiper systems.
- Glass inspection: check for pitting or coating residue; confirm blade compatibility.
- Replace or tighten arm, replace blades, replace motor or linkage as needed.
Common repairs & expected outcomes
Simple / low-cost
- Replace wiper blades (every 6–12 months or sooner).
- Clean blades and windshield; replace washer fluid and clean nozzles.
- Tighten arm nut or re-seat blade adapter.
Moderate
- Replace wiper arm (bent) or replace connector/adapters.
- Replace or lubricate linkage bushings and pivots.
- Replace washer pump or clean nozzles properly.
Major
- Replace wiper motor (including park-switch assembly) if torque or park function fails.
- Replace entire linkage assembly if joints are seized or splines stripped.
- Repair wiring harness or replace control module for auto-wipers.
Outcome: Fixing the root cause restores clear visibility. Regular blade replacement and cleaning prevent most streaking issues.
Urgency — when to fix immediately
- Immediate (stop driving in heavy rain): no wiper movement at all — major safety hazard.
- High priority (same day): intermittent operation, wipers stop mid-sweep, severe streaking that significantly reduces visibility in rain.
- Routine: minor streaking or occasional chatter in light rain — still replace blades soon.
Preventive maintenance & best practices
- Replace blades every 6–12 months or when you see cracking, skipping or streaking.
- Clean blades & windscreen regularly — oil and road film are the main causes of smear.
- Use quality blades (OEM or trusted aftermarket) and the correct type for your vehicle (conventional, beam, hybrid).
- Check arm tension — a weak spring means poor contact; have arms replaced if spring is worn.
- Park wipers upright in winter to avoid freezing to the glass.
- Use proper washer fluid with de-icing or detergent properties — avoid silicone or petroleum additives that can contaminate blades.
- Inspect linkage when replacing blades if any movement feels loose or sloppy.
What to tell your mechanic (copy-paste)
“My wipers are [not working at all / working intermittently / leaving streaks / skipping / stopping mid-sweep].
- Symptoms: (motor noise present / motor silent / blades chatter / only one blade streaks / washer spray weak).
- What I checked: (new blades on X date / cleaned glass / fuse checked / fluid topped up / observed motor running but blades not moving).
- When it happens: (always / only at high speed / only in heavy rain / after parked overnight in cold).
- Car: [Make / Model / Year / mileage].
Please inspect the wiper blades and arms, linkage and splines, test the motor and park switch, check fuse/relay/wiring, and test washer pump and nozzles. Thank you.”
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