I would go ahead and take a single edged razor to the two rubber plugs under the rear (trunk?) well (try the right passenger side first). Slice an 'X' into it and if water comes flowing out then that pump module is probably 'toast'. If you slice the 'X' evenly the resulting 4 tabs will 'sort of' self seal (don't go too crazy with the razor). It still could be water damage if any water intrusion has since dried up, so if slicing those 'X's in those plugs in the well does not result in water coming out then you just might have to go ahead and remove the side rear trim panels and lower center rear trim panel to get the lower well Styrofoam inserts out so you can inspect the right side modules near the bottom of the well. I just sliced up those Styrofoam inserts (carefully, there is a bundle of wires/tubes leading to that module that you do not want to short out) and slid them out not knowing how to get them out until much later. Anyway, when you get to that module, carefully unwrap (If memory serves me it is wrapped up in something) and check for corrosion. If that module is corroded you may have to replace it. Post back if you found water in there after slicing those 'X's in them plugs, or if after removing the Styrofoam inserts you find corrosion damage. Good luck!