can someone guide me in the right direction to find info. or pictures and or, any other information on the engine compartment wiring for a 89 mustang which has been converted from a 4cyl. to an 8 cyl.

Hi everyone, I am new to this forum. I have an 02 Buick Century Custom,V6,auto,air,loaded. 73,000 miles. I take extremely good care of my car. I had a new windshield put in vehicle about 6 weeks ago. About 5 days after, it rained cats and dogs and there was water sitting on the floor mat on the passenger side. I was also using the AC. This has continued since. Last week I was looking under up under the dash and what appears to be part of the blower motor(this is what we identified it from in the Haynes Manuel), was saturated with water. It is about 3 to 4 inches in diameter and has a type of filter on the bottom with a hose leading out of it. The filter was saturated. There are no strange noices, smells, nothing different everything runs the same. Does anyone know, could the water be finding its way in from the windshield or from some place else. Thank you for your help. Debbie