Battery?
How do you know the battery is good?
Place the key in the II position. Climb under the vehicle and jump the starter (connect a lead from the main post to the small post). A remote starter switch is ideal for this situation. If the starter gives you the clicking sound than you have a bad battery.
Ensure all electrical connections are tight and corrosion free. Once you have the vehicle running check the alternator output [~14V]. Your battery should be reading nearly the same while the vehicle is running. A battery with the engine off should be between 12 and 12.5V.
1990 RRC, 3.9L, AUTO "Willow Pond" (Sold)
1996 D1, 4.0L, AUTO "Lucas"
1999 RR, 4.0L, AUTO "Belle" (Sold)