I had this EXACT problem... Couldn't drive at night for days!
Took it to a specialist and they replaced the rear sensor on the axle (which wasn't faulty...) but it was only like £2 or something.
Anyway, basically I'd wound them out to far and the arms had popped out of the adjuster, therefore they were pointing REALLY high and wouldn't go back down. If that makes sense. (The little electronic adjuster with the white alan key on top pops out of the unit (apparently), and you'll see there's an arm that goes inside, this is meant to be connected somehow.)
The same garage fixed it for me that replaced the sensor. They did it for free, although they said it was a pain in the a**, so I'm pretty sure they wanted to charge for it!
Hope this helps, even though I can't tell you how to fix it! lol