You might also try pulling the cap off the end of the signal stalk and cleaning all the parts inside. I has issues with my wipers randomly turning themselves on and there was some moisture inside under that cap. Once I cleaned it out haven't had a problem since. The cap snaps off, but you have to gently pry it off. Make sure you pay attention to out it all comes apart. There are several parts inside. And don't let the cap fly off, it's spring loaded, and you may loose parts.

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