[trit21]

On my 2000 3500 Open ( I would think they are identical to the 1999 model) the water heater is actually under the helm and access to it is behind the rear most cushion on the u shaped seating in the cabin. Remove cushion, remove rather large access panel and there are the fresh water pumps, battery charger and hot water heater. I would only assume the hot water heater can fit through the opening as I have need measure mine but at least when replacing you can be inside the air conditioning. Let us know how replacement works and if HW tanks comes out the access hole.