My rear wiper is leaking window solvent down the tailgate for no reason. This will happen even if I haven't used the rear wiper and/or washer for a month. I will get back from a drive and when I walk around to the tailgate, there is solvent all over my tailgate and rear bumper. It doesn't happen every drive, and it has even happened just sitting in the driveway while I was waxing it.

I had the vehicle in for its 15k service last week, and of course they could not duplicate the problem, therefore they could not address it.

The leak is coming from the 2 holes that the solvent normally sprays from. I have ruled out any problems with the wiper assembly. I'm guessing the pump is somehow delivering pressure to the fluid line when it shouldn't?

Anyone had this problem?
'07 3.6 premium (early '06 build date)