Each tank has a single pressure sensor threaded into it near the bottom of the tank or along the bottom of the pipe leading from the tank to the dump valve. The cable going to the sensor looks like a telephone wire and plugs in the same way. It could be as simple as the plug is not seated well, or the sensor is at fault. Some have said they can see or feel the sensor by following the wire down in the hole under the closet. Is the trailer still under warranty? If the sensor is replaced, it needs to be calibrated.
Air Safe Hitch, Reese Dual Cam 800#, Centramatics