It’s an alarming experience when your wipers stop working in a heavy downpour, especially at highway speeds. You don’t miss wipers until they don’t work.
When your wipers stop working, and you can hear the wiper motor running. The problem is most likely a disconnected wiper motor link arm. Refitting the link arm is usually a simple process.
- Remove the wiper arms
- Remove the wiper cover
- Refit the link arm
You’re lucky, this is a pretty simple job, however, some cars are easier than others. In this post I’ll outline the most likely fault and what action you can take to fix it.
For wiper motor replacement and wiper assembly removal, check out “How to replace wiper motor.”
How Does A Wiper Assembly Work?
A windshield wiper system that you can rely on is crucial, as you know only too well. Wipers like headlights are mission-critical bits of kit. A typical wiper system consists of :
- Wiper assembly
- Wiper motor
- Wiper arms
- Wiper blades
- Wiper fuse
- Wiper relay
- Control module
- Wiper switch
All these components are equally important and crucial to the function of clearing the windshield. A wiper system like any system suffers from common problems. In your case, the problem is with the wiper assembly.
The wiper assembly is like a chassis for the wiper system, it’s bolted to the bulkhead just below the windshield. The motor, wiper drive mechanism, and wiper arms are all attached to it.
When activated a wiper motor rotates continuously and more sophisticated motors rotate left to right.
The challenge is to transform the rotational movement of the wiper motor into lateral movement of the wipers blades. The drive mechanism does this using a link rod from the motor to the wiper arms.
What Causes The Wipers To Stop But The Motor Keep Working?
You’re well on the way to figuring out the problem with your wipers as you’ve already diagnosed and found the wiper motor is working.
That info allows us to guess that most likely, one of the link rods has come loose. Your wiper mechanism may have more than one link rod. Usually, the link rod from the wiper motor to the wiper arm drive mechanism is the one that fails.
The mechanism is basically a collection of link rods with (usually) plastic socket bushings at either end. The rods push-fit onto the ball fitting of the motor and wiper spindles.
The link rods’ function is to transfer the motor movement to the wiper blades and seems to be the weakest link in most wiper system assemblies.
What Causes The Link Rods To Come Off?
The most common reason for the link rod jumping off is to wear and tear on the link rod plastic bushing. Other reasons include:
- Heavy packed snow on windshield
- Frozen wipers
- Incorrect wiper blades
- Wiper blade timing
- Worn wiper blades
- Worn wiper spindle
- Operating wipers on dry windshield
- Wiper arm vandalism
Wear and tear:
Link rods are attached to the wiper motor and also to the wiper spindles. They are attached by a bushing, commonly a plastic socket on the link rod, a metal ball on the motor, and a wiper spindle.
The plastic bushings simply wear out and refitting it may work for a while but eventually will need to be replaced.
Turning on the wipers to clear heavy snow will cause excess pressure on the link arm bushings. You’ll find when link rods jump off once, they’ll keep jumping off.
When wipers are stuck to the windshield solid, turning them on as you can imagine just like packed snow, causes huge pressure on the plastic rod link bushings.
Wrong wiper blades:
Wiper blades that are too long can catch in each other and also ride over the window edge which will load up the link rods.
Wiper timing off:
Wipers overlap as you know, but over time as the mechanism wears, the timing goes out. This can cause the wipers to catch in extreme weather conditions.
Worn wipers blades:
Worn-out wiper blades won’t slide across the windshield like new ones, that too puts a load on the rods.
The spindles are what the wiper arms are fixed to. They work hard and can bind as they get older. The binding can cause the link rods to pop off.
Running the wipers on a dry windshield can cause the links to jump off, but the real problem is as you know a worn-out link rod socket bushing.
How To Refit The Wiper Motor Link Rod
Fitting the link rod isn’t that difficult, however, getting access to the wiper assembly sometimes can be. On some cars, you can reach under the scuttle panel and snap the rod back into place. But most will be a little more work, especially higher-end models.
A workshop repair manual covers every aspect of car operation, maintenance, and repair including troubleshooting sections, for a few dollars they contain a ton of useful info.
If you need to replace the complete wiper assembly check out this post – “How to replace wiper motor”, and if you need a wiper assembly, check out the Amazon link below.Amazon Wiper Assembly
I’ve outlined the more complex process here.
Pop the hood and check access to the wiper assembly. Some cars will require removing the wiper arms and on others, the scuttle panels can be wedged open just enough to get the job done.
Turn ignition on and set wipers to the off position, turn ignition off.
Close the hood and remove both wiper arms. Note: a special wiper arm puller makes this job easy but most arms will come off using the following technique – Open the wiper arm fixing cover, remove the nut, but not all the way.
Now wiggle the arm loose by pressing and pulling on it firmly. This breaks their hold on the wiper spindle, now remove the nut and remove wipers.
Check this post it covers removing the arm using a puller – “How to replace windshield wiper motor.”
Remove scuttle panel, or just wedge open enough to gain access. Refit the arm, press it firmly back onto the ball socket fitting, or replace the arm. If the arm jumps off again, you’ll need to replace it, the plastic ball joint socket is simply worn out.
Rebuild in reverse order. Before testing the wipers, lift the arms off the window. This prevents damage to the hood or wiper assembly if by chance the wipers are fitted incorrectly.
How To Prevent Link Rod Jumping Off
Wiper link rods are pretty durable, but as cars get older the plastic bushings wear out and get brittle. There’s not much you can do about that, but you can avoid problems with your wipers by following a few simple tips, most of which will be obvious.
- Clear snow before turning on wipers
- Use deicer on frozen wipers
- Lift wipers off windshield when frost expected
- Use antifreeze in windshield wiper wash bottle
- Fit new wiper blades before winter
- Spray lube on the wiper spindles
- Clean and polish your windshield
- Use a windshield repellent like Rain-x
I use glass maintenance products that remove water and make night driving a ton easier, check them out here on the Car cleaning tools page.
Why would windshield wipers stop working? The most likely reason a windshield wiper stops working is a blown fuse. Other common causes include:
- Faulty relay
- Link rod disconnected
- Faulty wiper motor
- Faulty wiper switch
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