This may sound dumb, but I grounded the under-hood wire to something too small to work (AC removed, so I used one of those brackets) Dunno what was up, but it was a bad ground for sure. The kit still sprayed but the light wouldn't come on. I extended the ground wire and tied it to something more sturdy. Then it worked fine. Maybe the ground worked loose? Hopefully you'll have an easy fix, good luck.