Wiper Fluid leaking from tailgate

I have a 98 S10 Blazer that leaks wiper fluid from the rear of the vehicle. It is not in the tailgate, but from inside the body. There are rubber plugs to seal dust and moisture out, it is dripping from one of these plugs. I filled the reservoir under the hood, and when I tried to operate the rear window washer and wiper, fluid drained out the the rear. Does anyone have any experience with this. How do I trace the path of the hose. Do I need any special tools? Does anyone have any exploded views of this?