Try poking the nozzles with a pin to unblock them. If that doesn't sort it, check if the washer motor works - it should make a buzzing noise when you operate the washers.
I always takeout the nozzles and place them in a container with soapy hot water and leave them for a bit, once cleaned you can blow through them to make sure they are working.
If you live in a hard water area you may find the blockage is due to limescale build up, so remove them as suggested but stick them in the kettle when you are descaling it and it will do the same to your jets.