I never used the sink pump but being the neurotic sort of person I am
(Always touching the fridge vent on the way past checking it's still
on), every now and then I turned the faucet for a second and always
heard the pump.

A few weeks ago I decided to try it for real. I filled the water tank
and turned on the faucet. Some water came out and the pump was running,
after 5 seconds it stopped. I assumed the pump had gone or a fuse so I
turned it off. 10 minutes later I tried again and once again the pump
ran, water came out then it stopped again. Now nothing I do will get it
to run again.

Does it have a pressure switch like a travel trailer would.

If so, could it be blocked and have enough pressure stored to keep the
pump from kicking in, even weeks later?

Is there a fuse I'm missing?