I will do some digging when I bring my trailer back home next weekend - sadly we have to store it
I have some idea of where to look for the valve. I did get pressure - I am not sure how this works - I am thinking it is pressurizing the water tank to push water up - it seems to turn on and off for a while - but when low - it never turns off at all.
I guess we all are hunting for dumping locations - so my thought is fill the black and grey tank with soapy water and dumping friday when setting up to camp.
Here is hoping it all comes clean
Thank you all for soo much help.