I have a 2000 Mercury Sable LS with a unique problem - the windshield wipers don’t work when it’s raiing! More specifically, it’s cold temperatures and snow that shuts them down every time. They work fine in the summer rains, but if there’s snow or freezing rain while you’re shopping at the mall, they won’t work when you come out. I have not been able to get the problem to duplicate for a mechanic. Cold temperatures cause them to shut down, so we’ll leave the car outside a shop overnight. They’ll check and sure enough, no wipers, but as soon as they bring it in and start prodding around, they start working. Mercury had a recall on that year to install some kind of shield over the wiper motors, but that’s been done. Cold, wet weather is the problem. I hate to have to get rid of the car just because the wipers are temperamental, but it’s causing anxiety attacks every time it’s cold and wet outside!
There are switches inside the wiper motor. The surest fix would probably be to replace the wiper motor (they come with warranties). This would be cheaper than replacing the car…I think (?).
Or it could just be that the motor is really borderline, and even a little bit of freezing will stop them. I second changing the motor.