Wow!thanks for all the replies... the rig is a r-vision truelite b+ 285 plan its really a C but there is no bed over the driver/passenger. Instead of a bed, that is where the entertainment center and some storage. As far as build up, I'm almost certain you're right. We have hard water here and loaded with stuff that pits up all the chrome if not kept wiped off. But we also are out in the country and could be we have had mice chew wiring. My problem is the construction of the unit keeps me from access to the FW tank and cant see if wiring is bad. Even if i could use outside sensors, I still could not get to wiring to connect to monitor panel. So, next question would be, is there anuthing I can add to the water to clean the sensors?
BTW I have done a lot to our RV like re doing the electrical power panel, TV and sound distributin etc and would be glad to show pictures and diagram of what i have done if aynone is interested.... Thamks again