I thought the starter had gone bad on my 06 4.7. It was just clicking when I turned the key, even with the battery on a charger.
I did some searching on the internet & found this tundra thread. I took off the battery terminals & chassis ground and cleaned them thoroughly, & sure enough she fired right up.
Hope this helps someone else!
SOLVED! New starter...same result...help what am I missing | Page 3 | Toyota Tundra Forum