Water tank gauge says empty when its full

[Nathan]

Hi, on a recent trip out with my Swift Sundance 630L I noticed the warning alarm sounded repeatedly indicating the water tank was empty. When I inspected the water tank it was full.
Is this a common problem and if I need to replace the water tank gauge is this something I can easily do myself or does it require a trip to a dealer?
One other thing, one of the internal cab lights has gone out. Any idea where I can get my hands on replacement LED lights suitable for a motorhome from?

 

[Flicka]

Hi Nathan - The "sender" is usually 3 (maybe more, but that would be unusual on a Swift) contact points in the waste tank side wall. If you crawl under your van you should see wires connected to the tank. The metal on the inside is what sends the signasl to you control panel. The problem is generally grease or debris on the "senders" inside the tank, which stops the water being in direct contact. It is difficult on most waste tanks to access the interior for cleaning these "sender" points without removing the tank from the van. The easier option is to drain the waste tank, partly refill with water & bleach (approx 1/3rd full) then take the van for a drive, so that the contents are swilled around in the tank. If you can access the "sender" points a wipe with a cloth will usually clean them sufficiently. I've also had success using cheap Cola (2 or 3 x 2litre of the supermarkets own brand)

 

[BernieC]

I too have a Swift and have had this issue in the past.

The gauge sender on my Sundance 530LP is mounted on the top of the tank and accessible through a trap in the MH floor. In my case the problem was diagnosed as a build up of a scale deposit on the negative electrode rod of the sender unit which in total has five rods. The unit is relatively easy to remove being held in by four self tapping screws through the top. Remove the screws and disconnect the multiplug will allow you to lift out the unit and be able to examine it in detail. The negative electrode is one if the two longer porbes and if scale build up is the issue then this will be obvious from the colour, a white to light brown and rough surface feel of the rod.

I cleaed my negative electrode by scraping the depost off with a thumbnail but a should also be able to use a plastic scouring pad without any detrimental effect on the electrode.

Since cleaning mine we haven't had any other issues with the sender. We did noteon the odd rare occasion that the low level water alarm was triggered when the spark igniter button was pressed on the hob. The only solution to this was to shut dowwn and the restore the DC power with the "Power" button on the control panel. This hasn't happened now for some time but is more than likely due to a dodgy or missing earth connection to the motorhome through the hook up cable.