12v electric problems ? pump not working

[Jen21890]

hi, hope someone is able to help!
checking over our 1997 abi globetrotter jubiliee before our trip to cornwall next week and canot get the water to run.

when the pump is turned on and taps are opened no water comes out and the battery light on the panel turns from red to green. all was working fine before we packed up for the winter. the 12v lights work but does not seem to powering the pump. light turns green again when taps closed
have charged the battery fully and taken it to be checked at halfords - seems fine.
pump working fine - checked on brothers caravan.
fuse changed inside the van as one had blown but still not working.
tested briefly a few weeks ago after battery had just been charged and water worked straight away but not geting anything out now. seems like an intermitent fault somewhere but not any good with electrics so dont know where to start!

 

[Bingle]

When you turn on the taps, can you hear any distant hum from the pump (do you remember hearing any noise when water was flowing previously?). It's the best place to start, although I've no idea how accessible the pump is on your van, if there is an electrical fault.

 

[timhowarduk]

EDIT I cross posted with Bingle... his question is also my first assumption and worth checking!

So in summary a pump that is known to work does not run on your van when you turn on a tap? So you don't hear the pump run.

There are two ways turning a tap on can result in the pump running and water flowing.
Either every tap has a microswitch in it so when you turn the tap on the pump knows to run. These are very prone to sticking/breaking, and I would guess as your ABI is a similar age to mine it uses this system. It would be unusual for the bathroom and kitchen ones to all fail together though, so I would try a different tap to prove/disprove this theory. You can sometimes access the wiring by pulling out the top drawer.
The other possibility is that someone has fitted a pressure switch so when any tap is operated the pressure drops and runs the pump. If you see this system you will see the switch inline on the water hose in the locker, just the other side of the wall from where you plug the pump in. These can be adjusted and it is possible it is just out of adjustement.
Whichever kind of switching you have, prove it is the switch by opening a tap and bridging the connections, and then replace it.
The last possibility is that the 12v feed is not reaching the switch. You really need a multimeter at this point to test out what is happening.
If you have the manual, it contains a wiring diagram. If not say so and I'll supply a picture of mine and it might be the same....

 

[Jen21890]

No hum at all where there was previously.
Definitely don't have a microswitch

 

[audiorob]

Not sure what taps you may have - but when I had a similar problem it was that the filters in the tap ends had become blocked with debris - so the shower tap worked but neither the sink or washbasin. My taps have a threaded spout end that needs cleaning periodically, especially as the in-line filter can deteriorate over the winter and then shed gritty bits when water is again run through.

 

[timhowarduk]

The fact a lamp changes colour when you open and closes a tap suggests the switching is working. Sorry,I missed that. It sounds as if everything is working up until the final feed to the pump.
It is worth checking fuse (yep check it again, it might have gone again). If it turns out the fuse has gone again then there is a short circuit or fault causing it to go. It might yet be the pump, as your brother's van might have a higher rated fuse or even no fuse (as mine originally had)
At this point you need a test meter; to check continuity of the fuse, to check the back of the pump terminals in the locker, to check the 12v pump output from the panel, etc.