A drawing of the connection of the 2 hoses at the engine is shown on the bottom right of pdf page 120 on your 2002 Sightseer WPD27C parts diagram
http://www.winnebagoind.com/service/...GO/2wpd27c.pdf (Both Workhorse and Ford Chassis versions are addresed). The 5/8" hoses (reffered to as item 17 [see list on following page]) connect to the 2 "tees" (Item 16). All of these items are installed when the Motoraid Option is installed. The tee's are inserted into the front dash heater hose lines. You can purchase standard 5/8" copper tees and the clamps to install them at any normal auto supply house.
From a post I made on another forum:
Because motoraid heats both water heater and rear register, water is allways flowing through hoses (no valves along the way). Hose to water heater input connects to a tee in the intake manifold to front dash heater hose. Water heater output hose goes to input connection on rear heat exchanger (fan motor control on dash). Rear output hose goes back to engine radiator. If rear heater is not getting hot then there is blockage or someone installed a shutoff valve. While the front dash heater has a vacuum controlled valve, the motoraid bypasses that so water heater can be heated in summer or winter.
I do not know why, but I understand for several years now, Winnebago only installs the motoraid feature on gas rigs, not diesel. Some diesels may have a variation of this if they have a Aqua-Hot (formally called Hydro-Hot) system. However, do not take all that as an absolute because things do change at times
Dave