Hmmm, does the "click" only occur when the engine is hot?
It could be the starter solenoid going bad, but...
You also need to clean the terminals / cables on / at the battery.
Check the battery cables themselves...
Check the battery voltage with a multimeter...
This piece is probably missing on the majority of ihs, but IH put a heat shield on the pass side exhaust to shield / deflect heat from the starter.
Another extremely slim possibility:
many years ago, I had a battery "go out" in a "strange way" (to me). Car would start fine cold. If I ran errands and stopped for just a real short time (a couple minutes), when I came back the car would not start. I would stand around for 10 minutes and the car would start right up. After a couple times, I replaced the battery (the battery was "real old" -- 8 - 9 years on a 3 yr warranty battery. The longest any of my car batteries has lasted.)
hth