What Causes the Car Wiper to Not Turn Off?

[LeOlivia]

If the car wiper cannot be turned off, it is likely that the automatic mode is activated, and there is water falling on the windshield, causing the wiper to keep working. If the automatic mode is not activated and the wiper still cannot be turned off, then there is an issue with the wiper switch, and the wiper switch assembly needs to be replaced in such cases. The rubber of the wiper can adhere closely to the windshield, allowing it to remove dirt and water from the windshield during its back-and-forth motion. However, rubber products can age over prolonged use. Aged rubber tends to harden, and hardened rubber cannot maintain close contact with the windshield, leading to ineffective wiping and even causing unusual noises during the wiping process. Wipers need to be replaced periodically, but there is no strict usage period for wipers. They should be replaced as soon as issues like ineffective wiping or unusual noises occur.

[LaArianna]

I've encountered the issue of car wipers not turning off before, and it was really nerve-wracking during heavy rain. Mainly a few things can go wrong: the most common is the switch getting stuck, where the contacts inside the control lever get stuck and can't return; then there's the wiper relay failing, where the metal pieces inside burn together causing the circuit to stay on; another possibility is the wiper motor itself short-circuiting, allowing electricity to bypass the switch and keep it running. Damaged wiring causing a ground fault can also abnormally keep the circuit on. This malfunction is particularly dangerous—if the wipers suddenly won't stop on the highway, it not only affects visibility but can also interfere with driving. Quickly try flicking the control lever on and off several times; if that doesn't work, pull out the corresponding fuse as a temporary fix, then head to the repair shop ASAP to have a mechanic check the wiring with a multimeter. Remember to take photos of the setup beforehand and send them to the 4S shop—it can save diagnostic time.

[LeKiara]

A couple of days ago, my car's wipers had the same issue. When I took it to the auto repair shop, they found it was a problem with the linkage mechanism. The mechanic said the control switch tends to get stuck, and if the spring plate rusts, it won't spring back. If the relay coil shorts, it sends out erratic signals. Water ingress into the body control module could also cause program errors. Excessive wear on the motor's carbon brushes can lead to internal short circuits, making the wipers run even when the switch is off. Aging and cracked wiring harnesses grounding out is especially dangerous—it's like directly connecting to the power source. Remember, if this happens during rain, turn on the hazard lights and slow down first—don't rush to manually adjust the wipers. Nowadays, repair shops can perform full-vehicle circuit scans and read fault codes with an OBD diagnostic tool, which can basically determine whether it's a mechanical or electrical issue. That's much better than us trying to figure it out ourselves.

[LeCorey]

Uncontrolled wiper movement is mostly due to control circuit failure. From my experience, relay contact welding is the most troublesome issue. When operating wipers in rain with heavy load, low-quality relays are prone to sticking. The slide rail in the combination switch assembly tends to jam after prolonged use - spraying some rust remover can temporarily help. Modern vehicles using body control modules have relatively high failure rates, especially flood-damaged cars. Modified vehicles are even more problematic, as aftermarket wiper motors with mismatched power ratings can easily burn out driver chips. In such cases, don't force the switch as it may damage the transmission mechanism. For temporary solution, you can pull out the 15A wiper fuse in the engine compartment fuse box. The safest approach is to disconnect the battery negative terminal after the vehicle comes to complete stop. For older vehicles, focus on checking wiring harnesses, especially wires near the firewall which are particularly susceptible to wear and tear.

[HazelLynn]

I've helped my neighbor troubleshoot this issue before – the wiper linkage on his old car was completely rusted shut. There are three main root causes: the most common is switch unit failure, where the stalk mechanism wears out causing poor return function; actuator failures like water ingress short-circuiting the motor; or control signal abnormalities possibly from the ECU or relay box. Electrical shorts are dangerous – continuous wiper operation for ten minutes can overheat the motor, potentially warping plastic components in older vehicles. As emergency measure, locate and disconnect the wiring harness plug under the steering column, though positions vary significantly across models. During repairs, pay special attention to the motor gearbox – unlubricated gear sets create extra load on the motor. Recommend applying specialized grease to wiper linkages during biennial maintenance checks.