when I turn the water tap on after a minute or so the water stops and starts quickly,also the waterpump light flashes,is it an indication of the pump getting tired.
Have someone turn the tap on whilst you watch for any leaks where it plugs into the side of the van, check that the '0' ring is not split, as it sounds like it's draining backwards through either the pump or the '0' ring.
Regarding if it's tired or not .... you never know when it will pack in ..
Andy.
As a rule of thumb it is sensible to carry two submersible pumps on your travels as they can fail without warning. Buy a new one and try it. If the new one doesn't work the it's a matter of tracing the wiring back to the fuse box. Do the checks Kev and Sprocket suggest too.