Dear Car Talk:

I know my car intimately. We’re on a first-name basis, and I am quite familiar with what is working correctly and what is out of whack. So when I took my Ford Fusion to the dealer, telling him that there was something wrong with the timing of my intermittent wipers, of course he found nothing amiss. I told him that it didn’t happen every time I turned the wipers on, but every now and then the timing of the wipes was weird. That was three years ago. It’s only gotten gradually worse since then. Now, when I turn off the wipers, they sometimes stop mid-wipe, in the center of the windshield. That’s not good. Also, sometimes the intermittent setting works, and sometimes the wipers just keep wiping continuously regardless of the setting. — Marge

We believe you, Marge. The problem is most likely a bad wiper motor. The wiper motor contains the circuitry that’s supposed to make the wipers finish their current wipe, and park themselves at the bottom of the windshield, no matter where they are when you turn them off. But it also could be a bad wiper switch. The switch (the multipurpose switch on the steering wheel stalk) sends a current to the motor. And if the current is inconsistent, that could cause strange wiper behavior.

The best way to test the switch is to have the wipers misbehave when the mechanic has the car at the shop. That way, he can test the current at the wiper motor. If the current doesn’t change while the wipers misbehave, then the switch is fine. That means it’s almost certainly a bad wiper motor. Either way, it’s going to “wipe” a few hundred bucks out of your checking account, Marge.

And you may want to consider searching for a mechanic who is more inclined to believe you. While a wiper motor might not be a life-or-death issue, you’d like to know that if you came in complaining of something potentially serious, your mechanic wouldn’t brush you off as “that wacky Marge who’s on a first-name basis with her car.” You want him to say: “Oh, that’s wacky Marge. She’s on a first-name basis with her car, but she knows what she’s talking about.”

My 2018 Subaru Forester recently suffered the effects of a small, flying, hard object hitting the windshield while I

was driving on the freeway at freeway speed. What started as a small ding at the bottom of the glass eventually became a vertical crack one-third of the way up the windshield.

My Subaru is equipped with the EyeSight safety system, which includes automatic emergency braking. In order to guarantee the system’s performance, Subaru insists that the replacement windshield come from Subaru and that the EyeSight system be recalibrated to the new windshield. My dealer said the cost of the calibration was based on three hours of labor for a total of $405.

This seems awfully expensive, since the factory likely didn’t spend three hours calibrating it when the car was assembled. What do you think? Is this for real? The car is great to drive, and I do like the idea of having the additional safety provided by the EyeSight camera system, but don’t want to get ripped off. — Greg

Yeah, it seems to be real, Greg. The EyeSight system uses two cameras that look out of the windshield from either side of your rearview mirror. They operate like eyes with stereo vision, in order to judge distance.

We checked with Subaru, and they tell us that cars with the EyeSight

system use a specific windshield glass, so you do need to use a Subaru replacement. They say that after the windshield is replaced, the settings on the EyeSight cameras are cleared and then recalibrated. That’s followed by a test drive, to make sure the system doesn’t apply the brakes automatically for a taco truck at the side of the road, rather than a car stopped in front of you. They estimate the whole job takes three hours.

While these systems are, generally, great, they do vary in technology. Subaru has opted for this two-camera, binocular vision system. On the plus side, it’s relatively inexpensive to purchase, which has allowed Subaru to make it available to a lot more car buyers at a reasonable cost. More safety for more people is a good thing. On the downside, unless your windshield replacement is covered by insurance, you have to take out a home equity loan every time a stone kicks up at your car from a double FedEx truck.

So if you haven’t already done so, Greg, you should call your insurance company and find out whether it covers windshield replacement. Coverage varies by state, but if the crack was bad enough that it impaired your vision or made the windshield unstable, your insurance company may be required to pick up the cost — including the three-hour “EyeSight retraining course.” Good luck.

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