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Wipers Only Work On High : [ Reasons & Solution ]

Wipers Only Work On High : [ Reasons & Solution ]

While it’s true that windshield wipers may be a little fussy at times, this is still much preferable to total wiper failure. Windshield wipers are a must, much like new tires and auto insurance. The motor in the windshield wipers gets its juice from a switched 12-volt line.

The wipers not operating at all may be difficult to diagnose, but a single-speed motor presents fewer challenges. While the diagnosis may take some time, it is not difficult and only takes one instrument.

The wipers must have an internal problem if they only function in the highest setting. Let’s check out the cause of your high-speed windshield wipers not working.

What Is The Reason For My Windshield Wipers Only Working On High?

The relay switch activates the wiper motor and gears by sending an electrical signal to the module, and this relay regulates the speed. A malfunctioning relay limits the windshield wiper speed to the last signal’s setting, which is why the windshield works only on high.

The motor may have shorted out or broken if a windshield wiper doesn’t operate. Your wipers won’t function. Replace any worn components; although wipers may be the simplest, here are some tests you can do yourself.


The motor’s one-speed operation indicates electricity reaching the switch, but the switch might have failed. Bridge a multimeter between the upstream supply and switch contacts.

If each switch contact reads over 10 volts, the issue lies downstream. If just the high-speed terminal reads, the switch is broken.

These contacts may lose their “springiness” and fail to establish connection when the switch is twisted or slid like a lever, and they may get blocked with insulating atmospheric pollutants.

High speed, the least utilized, still works, suggesting low and intermediate speed connections are loose. If they can be twisted to increase tension, replace the switch.

Wire Harness

After testing the switch, check the wire harness. If the wiring harness is linked at either or both ends with a multiblock, study a repair manual to understand which wires and terminals carry which wiper speed signals; sketch a layout illustrating the wire colors, terminal placements, and their purposes.

With the switch set to “Low,” use a multimeter to measure the voltage between the low-speed terminals and the wiper motor. If so, the wiring is acceptable; otherwise, it’s faulty. Repeat at medium speed. If both circuits are OK, replace the motor; otherwise, the harness.


The wiper motor may have failed, getting the right signals from the switch through the connections but unable to function. Inside wiper motor housings are seldom user-serviceable; get a replacement from a dealer or salvage yard.

Alternative Methods

Faulty grounds cause a variety of difficulties. Some wiper motors use bolts that secure them to the body as a ground. Trace the motor’s ground wire to its mounting point, then smooth the bottom of the connection and the chassis mounting point using 60-grit or heavier sandpaper.

Replace and tighten the fastener. Dielectric grease at the contact sites improves the repair. If working on a vehicle with ground-through fasteners, remove the bolts, elevate the motor, and apply the process to the contact surfaces.

In some contemporary automobiles, a relay or control module is between the switch and motor. Untrained technicians may have trouble diagnosing and servicing these components.

If all other tests pass, have a trained auto electrician diagnose the car if the malfunction continues.

How Can I Improve My Wiper Performance?

You should have new windshield wipers every six months to ensure they work optimally. Wiper blades may get worn just as quickly in hot, dry weather as they would under normal driving circumstances.

You should consider getting new ones in autumn and spring to prepare for winter and summer. Don’t wait until rainfall notices that your wiper blades are worn out; they must be fully functional and ready to go far before any emergency.


The windshield wiper motor is 12-volt and is powered by a switched wire. It might be difficult to diagnose why the wipers suddenly stopped functioning but fixing a motor that only functions at one speed is much simpler.

Although diagnosis might be trying, it is straightforward and involves just a single device, but consulting a technician is always the best option.