I have a C-403L Thetford Cassette toilet in my 2006 Eriba. The flush as decided not to work and the blue light by the toilet is not coming on. I have had a look at the pump which looks ok (no burn marks). The fuse is not the problem. There is electricity coming through to the compartment housing the fuse - what other factors should I be looking at ! The only thing I can think of is there is something in the fuse box that is not working?!? Any advice gratefully received.

The last time this came up the member was not pushing the flush button in the correct place (I won't mention names) be sure you are pushing the flush button in the correct place ............. on the blue bit at the front of the panel.

It's quite common for toilet fuse blades to corrode so it may be worth changing it anyway - and treat the fuse holder to a squirt of contact cleaner while you're at it.

If the pump still refuses to work it may have seized.

Here's a quick way to determine this (without having to roll up your sleeves and snap on a pair of latex gloves):

Disconnect the mains hook up lead (or flick the caravan's RCD off) and switch on all the internal lights.
Now, when you press the toilet flush, a seized pump will draw a fairly hefty current which will cause the lights to dim quite noticeably.

You have not been charged for this incredibly useful tip

Thanks for that John. Tried your suggestions and still no luck. I attacked a new bump - not a peep. I think it must be with the electrics under to cover on the toilet top (under the blue light) or the ele block attached to the fuse? any incredible ideas how I could check them out?!?

Did you change the fuse in the cassette compartment? see my topic on changing a pump which shows how to remove the switch cover.

How to replace an electric toilet water pump <<<<<click here.


if all else fails try a mobile fitter there is a section on how to find one on the forum.

If you lift the switch panel off you'll see one (or two) edge connectors attached to the circuit board. Pull the connectors off and give them and the board's contacts a clean so they're back to shiny copper.

The connectors are IDC type (Insulation Displacement Connector), where each wire is pushed down into a forked pin to penetrate the insulation and make contact with the conductor - check that each wire is making proper contact and, if necessary, use the blunt edge of a craft knife to push each wire firmly into its pin.

Your model may include a reed switch to inhibit the pump when the holding tank is full, and either the switch may be faulty, or has corroded connections.

Another thing to check is the pivot in the holding tank; it holds the magnet to operate the reed switch and they sometimes come adrift - often caused by giving it too much of an aggressive shake*

I reckon that just about exhausts my knowledge of these rather overcomplicated things, despite having attended a course at Thetfords, although I don't like to brag too much about being fully toilet trained.

* when rinsing out the holding tank - what else were you thinking?

Well thanks for that!! Pretty comprehensive!!! I live in France and the nearest help I could get is a long drive so I am determined to sort the problem myself. If I need to replace the reed switch hopefully you might be able to advice me where I might buy one online? After looking at the problem using your suggestions.....I will report back. Regards Andrew

Hi, Andrew. Where are you in France? We live in the cotes d'Armor.

Hi there. Thanks for yours!! We live in Locmalo 56160 Morbihan. Been around this area for 20 + years - going back to the UK?.....NOT A CHANCE

Well have just tried all the suggestions and still no joy! Not sure what you mean or were to look for the pivot on the holding tank and the magnet? All electrical connections seem good. I think the fuse should be a "3" and I notice it has a "10" installed - when the bump ceased up could something on the electric "boards" have been compromised? Look forward to another installment of advice - YES PLEASE got to knock this on the head, her in doors not happy to use a bottle of water as a loo the flush!

Toilet manuals here

Thetford cassette toilet manuals

Zitat

---

Not sure what you mean or were to look for the pivot on the holding tank and the magnet?

---

This is where it gets exciting, the waste tank has a round bit on the top where the waste goes in......... remove that and inside there is a float arm with magnet attached the float lifts and lowers the magnet depending how full the tank is a sensor inside the tank compartment turns off the pump when the tank is full by detecting the height of the magnet.

if this equipment is damaged by the vigorous shaking while rinsing after emptying (as John described) that may be your problem.

Disclaimer............ if you get all mucky delving in there and its not the problem do not hold me responsible.

New cassettes are available if you want to go down that route but they are not cheap............... and be sure to get the right one ............. your model number should be just inside the cassette cupboard door.

pump 18.JPG - Bild entfernt (keine Rechte) pump 08.JPG - Bild entfernt (keine Rechte)

Cistern and chain? 🤡