Installed my seelevel gauges in my host mammoth today. Seems to be working great. Was able to use the existing wires. Next upgrade will be rear view camera.
Make sure on the fresh/gray tanks that there is no blocking foam touching the sensors.. they tanks move, and will peel back the sensors from the tank wall if anything is touching them. You will get wierd readings when the sensor trip peals away from the tank.
I had to trim away some foam to get mine to stop doing that.