I think 1995Brave is right, We had an 1987 Itasca and the pump was under the bed. On our 2001 it is in an outside compartment on the passenger side. Stim may be correct a valve may be open or sometimes it is hard to get the pump to prime after they have been drained to winterize them. Keep trying and you will figure it out.
Ed & Ruby & the 2 cats
2001 Winnebago Brave 30W
7.4 gas Work Horse Chassis
99 Jeep Grand Cherokee