Intermittent Wipers: How They Work and Possible Problems

Most windshield wiper switches have a low, high, and intermittent speed setting. The intermittent mode allows the wipers to stop between each wipe. This is especially helpful in light rain or misty scenarios.

What are Intermittent wipers?

Intermittent wipers are essentially windshield wipers that are equipped with an intermittent setting.

Just about every car since the ‘90s is equipped with intermittent wipers. It’s harder to find a vehicle without them than it is to find one with them.

Early intermittent wipers had a dedicated module, either built into the wiper motor (as on GM platforms, like in the illustration shown) or as a separate module under the dash (like on Fords) that would time the wiper sweeps and could be adjusted to time the sweeps closer together.

But in the mid 1990s, body control modules (BCM) or generic electronic modules (GEM) on Fords with internal timers with various timer functions began to appear. These modules will typically feed reference voltage to a potentiometer built into the wiper switch. The less resistance that “pot” has, the lower the reference voltage is. This is the input that determines wiper sweep timing. That being said, some GM vehicles had a standalone intermittent wiper module deep into the 2000s model years.

Where Is the Intermittent Wiper Relay Located?

Where there is a module, there are typically relays in the circuit (sometimes three different ones) that send power to the wiper motor for its various speeds. These relays are typically found in the underhood junction box/fuse panel with the other relays.

Where there is a module, there are typically intermittent wiper relays in the circuit (sometimes three different ones) that send power to the wiper motor for its various speeds. These relays are typically found in the underhood junction box/fuse panel with the other relays.

–Richard McCuistian, ASE Certified Master Automobile Technician

Some of the module-driven independent wipers will factor in vehicle speed and automatically shorten the time between wiper sweeps.

What are the Symptoms of a Faulty Intermittent Wipers?

When the intermittent wiper relay fails or wears out, it will show a few warning signs such as the following:

The Intermittent Setting Doesn’t Work

When the intermittent wiper relay fails, the windshield wipers won’t work when the windshield wiper switch is set to intermittent. When this issue is present, the windshield wipers can only work on high or low settings.

Note, however, that on platforms with multiple wiper system relays, symptoms may vary. If the BCM or GEM is the operational component, it will receive input from the intermittent wiper switch and will command the various relays.

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Pro Tip: A scan tool that can display BCM or GEM datastream (generic scan tools won’t do this) can provide a “window” into the system to see if the BCM is receiving inputs and processing outputs. Higher end scan tools with bi-directional functions can command the wiper functions. If the wipers won’t work right with the switch but will work when commanded by the scan tool, the switch or its circuits will be at fault.

The Wiper Moves at a Different Speed

Relays are electronically controlled switches, though only some intermittent wiper systems have relays. When they do have relays, the relay typically works or it doesn’t. Chances are, you use your intermittent wipers enough that you’ll be able to tell when they’re not working right, such as when the wiper moves at a different speed than normal.

How to Check Intermittent Wipers Yourself

You can check your intermittent wipers if you have a schematic and know how to read it. You can also look in your owner’s manual for pertinent fuse and relay locations. You may need to take your vehicle to a repair shop if a module needs replacing because most modules need to be initialized by a professional with special equipment.

Where to Get Windshield Wiper Motor Relays for Your Vehicle

While windshield wiper motor relays are not as crucial as the engine when it comes to your vehicle’s operation, they can still cause annoying issues. Fortunately, it’s easy to find replacements when you shop at CarParts.com, your one-stop shop for high-quality parts.

Find only the best prices when you shop from us. All our windshield wiper motor relays come with a low-price and lifetime replacement guarantee, helping you get the best value for your money.

You don’t have to wait long to get your new relays. All our parts are on hand and ready to ship from our strategically located distribution centers, so you can expect your order in as fast as two business days. Place your order using our website, or you can also dial our toll-free hotline for further assistance.

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