I recently bought a Hoover steamvac, and when I

I recently bought a Hoover steamvac, and when I tried using the upholstery tool in my van the other day, it didn't pick up any water. I tried reseating the dirty water tank several times to no avail. However, when I unhooked the upholstery hose and tried using the vac normally, it sucked up tons of water. So, the problem seems to be just when using the hose and upholstery tool. Any ideas?