Glad the switch was where ours is, as I suggested Paul, since it's easy access.
But I'd check your connectors as Bob advised, before doing a calibration that can "muddy" the situation as Fred noted. Recalibration may be an ultimate move here, but I'd still be suspicious of several tank measurements going haywire at once like this.
See if the image Bob supplied guides you. I also have a page or two of Aladdin system connections in my 2006 electrical diagram book if you need copies to help. Aladdin modules are a bit spread out in the coach, but most on ours are on the left sidewall of the tank bay, the one with underlatches rather than an integrated handlatch and that's just in front of the curbside rear tires. There may be a module in the front electrical bay too.
Check for secure connectors at all module ports, and for any corrosion on contact points that has added too much resistance in a circuit. A water leak into a bay could have compromised a master connector on one module, or more than one elsewhere on multiple modules, so using the diagrams we can provide should give some guidance and understanding.
I'd go first to both ends of the cable 38040425 in Bob's image above, since all 4 of your faulty readings, and only those 4, feed from the Tank Interface Module - that's just too much coincidence.
-Joel