rear window wiper
 

I just bought a 2006 Ascender with two very minor faults. The rear window wiper doesn't work. The other issue is that a seam in the back of the front passenger seat needs restitching. That I'll doe with a sailmaker's curved needle. But the wiper failure baffles me. The fuse is good because the front wipers work. Any suggestions (other than take it to an expensive mechanic)