Why won't my truck start after it rains on 2000 Oldsmobile Bravada

Took the truck to a local dealership to have the leak traced but still has the leak I guess had a good rainand now the truck won't start.

Asked by for the 2000 Oldsmobile Bravada
Only thing i can think of is water dripping on the distributor in back of the engine or you need a good tune up!