You should hear the pump going when you press the wash/wipe button, if not before deciding its the pump get someone to listen outside where the filler tank is. If not you pump may have gone or wire come loose.
Pump located in the base of the water holding tank [mine was] If you can hear the pump operate then first try cleaning the washer jets with a sewing needle or pin as the do get blocked.
Secondly check out the pipe hasn't come off the pump and any other pipe joints you can see.
Been through it all from blocked jets, pipes come adrift at joints and pump failure.
It's a pain job but that's all I can offer from experience of washer faults. Don't use washing up liquid for screen cleaning use only screen wash additive.
Nobby
June 2008