| Streaks or unwiped bands | Worn, hardened, or damaged rubber no longer maintains even contact with the glass. | Leaves areas of the windshield unclear, especially in heavy rain or at night. | Operate the washers and inspect whether clean water is removed in one smooth pass. | Replace the blade if streaking remains after cleaning the windshield and rubber edge. |
| Chattering, skipping, or vibration | Dry glass, wax or road-film contamination, a hardened blade edge, or an incorrect wiper arm angle. | Creates intermittent blind spots and can distract the driver. | Test the wipers on a wet windshield; do not run them repeatedly on dry glass. | Clean the glass and blade first. Replace the blade if the noise or skipping continues. |
| Squeaking during operation | Friction caused by aged rubber, dirt, glass contamination, or insufficient washer fluid. | May indicate poor contact and can become worse during prolonged rain. | Check the washer-fluid level and wipe the rubber edge with a clean, damp cloth. | Replace the blade when squeaking persists on clean, wet glass. |
| Visible cracks, splits, or tears | Ultraviolet exposure, ozone, temperature changes, ice, and general aging have damaged the rubber. | The damaged edge can fail to clear water and may separate from the frame. | Lift the wiper arm carefully and examine the entire rubber strip from end to end. | Replace immediately; damaged rubber cannot reliably be restored by cleaning. |
| Rubber edge is brittle or curled | Heat, sunlight, freezing conditions, and long periods of non-use have reduced flexibility. | Uneven pressure leaves water behind and reduces the cleared viewing area. | With the blade lifted, look for a rounded, hardened, or curled wiping edge. | Replace the blade, particularly before the next season of frequent rain or snow. |
| Unwiped areas in the center or at the ends | A bent wiper arm, weak arm spring, distorted frame, or blade wear prevents consistent pressure. | Important sections of the driver’s field of view may remain obstructed. | Inspect the blade while operating it and check whether the arm presses evenly across the glass. | Replace the blade if worn; have the arm or linkage inspected if a new blade does not help. |
| Metal or plastic contacts the glass | The rubber insert has torn, detached, or deteriorated significantly. | Can scratch the windshield and rapidly worsen visibility. | Stop using the wiper and inspect the blade for missing or loose rubber. | Replace the blade immediately and check the windshield for damage. |
| Reduced performance after cleaning | The blade has reached the end of its service life rather than being affected only by surface dirt. | Continued use may leave a hazy film during sudden rain. | Clean the windshield and rubber edge, then retest with adequate washer fluid. | Replace the blade when cleaning does not restore smooth, streak-free wiping. |