C2 Flush problem

[krazykiwiboy]

Hi.
I know there are many treads here all about Thetford C2 flush 'not working' but none talk about the odd problem I have. This is driving me bonkers!

We were away recently when the flush stopped working.

First thing I did was check all the fuses. Including the 2 amp blade fuse outside where the cassette slides in.
No problem there.

With the switch mechanism out, I can see one switch to ensure the cassette is in place, and another for the push flush operation. With a meter, I can hold these two switches down and verify that the circuit is then complete at the connector.
If I short across the other side of the connector, I can hear the pump work.
All good right?
After assembling it all again, NO flush.

Have disassembled / checked / assembled multiple times with the same result.
So I bought a new connector, thinking they're not mating well enough.
Still got the problem.

Is there something I'm missing here?

 

[Dustydog]

You say the fuse is okay. How do you know that?
These fuses and their housings were poorly designed by Thetford and placed in an hostile environment.
I suggest you remove the original fuse and get a new one. Try and clean the female parts of the fuse holder with fine emery paper. Not easy.
Now take some quality electrical contact spray and saturate the fuse housing.
let it dry and repeat the process. Now replace the new fuse and I am sure the flush pump will work.
Tell us how you get on.

 

[krazykiwiboy]

You say the fuse is okay. How do you know that?

' With a meter, I can hold these two switches down and verify that the circuit is then complete at the connector' - If the fuse connection was dodgy, then surely there would be some sort of intermittent connection here? With the mechanism out I can't get it to fault by jiggling wiring around, rotating the vent mechanism etc so the fuse and it's terminals etc must be making adequate contact (if not good). .

These fuses and their housings were poorly designed by Thetford and placed in an hostile environment.
I suggest you remove the original fuse and get a new one. Try and clean the female parts of the fuse holder with fine emery paper. Not easy.

OK ... I'll try again (again) .

cheers

 

[Parksy]

Our Thetford cassette toilet wouldn't flush and although the fuse and connections looked ok we changed the fuse, cleaned up the connectors and everything worked fine again. We think that the problem may have been cause by a tiny spot of mildew in the cassette compartment

 

[Dustydog]

I have found in the past the multimeter is a good tool but can give spurious readings. When yours measures ok you expect the circuit to be complete. However when a heavier current is required the resistance at the fuse holder can't cope and in my case problem solved.
As a matter of interest have you tried temporarily bypassing the fuse and its holder?
Good luck.

 

[chrisn7]

This is true. Our van had clearly had problems in the past, when I came to investigate non flush, as I found a 20 amp fuse in place of the 3 amp (I kid you not), as someone had attempted to overcome the resistance of the corroded terminals.
If these are deteriorated, replace, as you will never clean them up well enough to last long term. They only cost a few pence online, and they are easy to solder in place. Also check out the little circuit board, as its connector also suffers corrosion along with the tracks on the pcb where it attaches (they can disappear altogether) and you get no red warning full lamp. I cut the connector off and soldered the wires direct to the pcb to eliminate this, also a small poly bag inverted over the tower to protect from, well,whatever...

 

[SirRogerFFS]

I am not familiar with the C2.ours is the cw 250 with flush button on top of the tank.If this doesnt apply to the c2 it will help anybody with the 250 On the top of tank (250) there is the flush button there is a removable foil to let you into the top of the tank where you will find a printed circuit board with a push on connector. Remove the connector from the board and spray the terminals with WD 40 on the plug side and just clean up the terminals where the connector block fits.This maybe where your problem is it certainly was on the 250 .I hope this helps.Sorry forgot to mention that the terminals on mine were corroded due to condensation. Worked ok ever since .All The Best
Sir Roger