have someone sit in the car while you run a hose over your hatch area, then you'll be able to see exactly where's its leaking from

 

Make sure the drainson the sides of the hatch where the lift struts attach are clean. If they are pluged water will pool up next to the hatch weather stipping and follow the easiest path down.....Cleaned mine with a piece of #16 wire.

 

i had that, and i just drilled two holes in the plug under the spare and i don't have that anymore.

 

My 1998 GSX was rear-ended, and ever since it was repaired water collects in the spare tire well whenever I drive through a puddle, no matter how fast or slow. It never happens just from rain (I park it outside). The drain tubes are fine, and all the seals look good. Apparently it is coming in from somewhere below. The dealer hasn't been able to find anything wrong, and it's the best car dealer I've ever worked with, so no complaints there. And the water does something to the wiring back there that sometimes sets of my security alarm. Any ideas?