Volvo Repair: front windshield wiper spray, elbow connector, windshield wiper

Question
Regis,
1998 Volvo S70, front windshield wiper spray - fluid just dribbles out from each of both nozzels.  Your expert thoughts about how to diagnose the problem(s)?  

Wiper fluid is full.  I've disconnected elbow connector on driver side of hood, from under side and try to blow through but air does not pass through.

Thanks
Just trying to keep wife happy!  

Answer
there is a check valve behind the felt panel on the hood.follow the hose from drivers nozzle under panel to find valve it will need to be replaced.if this is ok then the nozzles could be clogged with wax and will need to be unclogged with a small wire.