Hi, we have a hobby caravan and just recently the shower stopped working. shower is separate from sink. Its always worked perfectly before.But when opening the shower tap theres just a tiny drop of water spurts out then nothing. I tried turning the bathroom sink tap on at the same time and then the shower worked , but stopped as soon as the sink tap was turned off. We have an onboard water tank. The kitchen tap and bathroom tap both produce a buzzing noise from the pump when in use but the shower does not.(cannot remember if it used to make a noise before this fault though). Please does anyone know how to fix it?