Thetford toilet

[GRS1661]

Hi all. My Bailey Pegasus Ancona has a Thetford C250 toilet which has stopped working.
I have replaced the top switch PCB , and the smaller internal control board in the cassette compartment. Put in a new fuse and cleaned the contacts .
The pump actually works as I wired a 9v battery to test it. Nothing I do seems to work.
Any ideas because it’s really doing my head in now.

 

[birdman101]

Is there actually any 12 volt getting to the toilet. Have you checked the fuse often marked pump. Is anything else on on 12 volt working. If not have you checked the main batter 20amp fuse.

 

[GRS1661]

Hi, thanks for getting back to me.
Do you mean 12v to the control board or to the actual pump ? The main 12V is working. Lights, ignition etc. . The main water pumps work fine, taps etc. is the “pump” fuse on the main breaker board ?
I was toying with buying a whole new pump & wiring loom but I can find a better use for £50

 

[IanB1485]

Cables tend to rot in the toilet , so given you have changed the main components ,what's left is the cables.The attached schematic is for a C260 series, the difference is minor in that the reed pcb is more simple in that it only contains the reed switch , and not the polyfuse and relay.

 

[GRS1661]

Cables tend to rot in the toilet , so given you have changed the main components ,what's left is the cables.The attached schematic is for a C260 series, the difference is minor in that the reed pcb is more simple in that it only contains the reed switch , and not the polyfuse and relay.

Thanks IanB
Not very good with wiring diagrams!
I’ve had the pump out and checked connections and wired a 9v to the cable ends and it works.
All fuses good.
Only thing I can think of is a broken control wire, but how to find which one ?

 

[rich0805]

Thanks IanB
Not very good with wiring diagrams!
I’ve had the pump out and checked connections and wired a 9v to the cable ends and it works.
All fuses good.
Only thing I can think of is a broken control wire, but how to find which one ?

Use a multi meter to check continuity of each wire

 

[IanB1485]

On one small motorhome I simply ripped out the wiring and replaced it . You can buy new wiring harness of thetford dealers and Ebay , one such link is :https://www.ebay.co.uk/itm/303467928291

 

[birdman101]

Cassette door open. Front right hand side floor, you should see a plastic plate which you can prise up. Then you should find a connector which connects the caravan wiring loom to the toilet. Pull connector apart and check for voltage on the loom side. If you have 12 volts this will show your fault is on the toilet only and not the caravan wiring,

 

[GRS1661]

Definitely 12v to the connector in the cassette compartment.

On one small motorhome I simply ripped out the wiring and replaced it . You can buy new wiring harness of thetford dealers and Ebay , one such link is :https://www.ebay.co.uk/itm/303467928291

definitely 12v to the connector in the cassette compartment.
Difficult to tell on the PCB connector.
I think it might come down to the full wiring loom & pump. I have just invested so much time & effort (and cash) chasing this round I hoped there would be an easy fix I had overlooked. !

 

[Dustydog]

Sometimes the pump will run off load, but once asked to pump water fails🤔

 

[Martin_E]

Definitely 12v to the connector in the cassette compartment.

definitely 12v to the connector in the cassette compartment.
Difficult to tell on the PCB connector.
I think it might come down to the full wiring loom & pump. I have just invested so much time & effort (and cash) chasing this round I hoped there would be an easy fix I had overlooked. !

I’d shouldn’t be difficult at the PCB, test the red and first black cables, you should get your 12v + on them, if you don’t try the red and the next black, if you have 12v + some plum has reversed the polarity at the connector in the cassette locker.

Pressing the flush button with tester on the blue and brown wire should come back with 12v + volts