My guess would be that the pump is by the water tank, which may be under the rear bed. Where is the water tank fill? It should be pretty close to that.
I also would check the little screen on the faucets.
Though the fact that you are not getting anything, sounds more like the pump is not getting primed. Pump should run for a few seconds (with all the faucets closed) and then shut-off. If it's continuing to run, it's not pumping water, or building pressure.
Are there any drains open under the RV? If it was winterized, and they left those open, that would be where your water is going:(
Good luck:)
