The story is went on 200km of dirt rd near Moree. When we went to set up found water pump dead and hot water heater - no work!!. Could dust cause these 2 problems? Or a lead been pinched. After getting mobile repair man and he considered it a electrical problem. I have by passed normal wiring and connected water pump and a yellow lead to heater ( I discvered) both working now , but where is wiring problem. ANY SUGGESTIONS? (THIS IS ALL 12V ISSUES)

Check fuses, connections & for damage in any wiring (esp near anything which moves).

Don't rely on visual inspection for fuses. Remove them (were they loose, any evidence of overheating?) & check for continuity with multi meter.
Like wise don't rely on visual inspection for connections - undo them & clean if necessary before replacing & ensuring they are tight.
Wit multi meter check continuity from battery to first connection, the firs connection to second connection etc etc to pinpoint the problem

Good news that the bypass works, confirming that the problem is a power supply one. So just a matter of checking through methodically.

Could be anywhere, but fuses are most likely I reckon, so check them first.

Keith you don't mention what type of van you have, but if you are unable to locate the fault after a good search, and your van has the wiring running through the walls where the fault will be hidden, a re-wire maybe the easiest solution.