The caps hide the jets. If you turn your headlights on and use the windscreen washer, the water pressure pops the caps up and the jets operate. If they don't do it, then they're bust - most likely to be the pump.
They came with cars that had the Winter Pack or Xenons.
Thanks Bobda ive just pulled the cap open slightly and i can see the jets. They are bust as are the windscreen washers, i cant hear either motor when i activate them and the fuses are ok so looks like im going to have to change the motors. I've had the car nearly a year and i just presumed my GT didnt have the headlights washers fitted because nothing popped out when i pulled the stalk Doh!!!
Im not sure if its the part of the world i live in but im struggling to find parts for the GT. Ive been waiting over a month for my windscreen to be replaced because nobody has any seals in stock, nightmare!! Still wouldnt swap her for anything else though