1999 RL 3.5 Electric Issues

Positive battery cable corroded and I changed the terminal connector. The cable built up corrosion within the week and I rinsed it off with boiling water. Recently while driving the wipers slowed and the brake light came on and the engine died. I boosted the engine and it ran for 20 minutes and when I shut it off it would not restart just emit a clicking sound. Starter? Alternator? Battery Cable? Thoughts.