Join Date: Sep 2016
Location: Costa Blanca Spain
My Motorhome: I drive... Hymer B550 Skyline
Thanked 35 Times in 35 Posts
Remove all cushions, lift all under-cushion wooden flaps and look for a water tank.
There will be a BIG screw lid . Unscrew lid, peer inside.
At the bottom of a plastic pipe, there will be a pump.
Since this is a German motorhome, chances are.... someone has connected the 12v the wrong way round
because the Germans are all colour blind....( only joking, Dorli ! )
Swap leads. You can't do any damage, but the pump will perform MUCH better when the leads are the right way around.