My 06 Camry clicks once when trying to start it.
 

I was driving to a store the car is running great I shut it off I did what I had to do inside and came back out to start it the car did nothing but click once the battery is fully charged I have tried different batteries and it still happens. I did a test on the starter relay and the test showed that the relay was okay. I pulled the starter out and did a test witch was successful. I cleaned all the grounds also the terminals on the battery. I have also tested the transmission sensor to see if that was bad. I am out of ways to figure this out any help would be much appreciated. FYI I tried a new starter and it did the same thing.

With starter on engine, if possible jump the starter solenoid and starter motor wiring directly to battery.

Use a jumper cable, etc between the +12v battery terminal and starter motor terminal. Determine if motor works.

Apply 12v to the small wire connection on the solenoid (runs to ign switch). Determine if motor engages.

It does happen the large electrical cable between the battery and starter corrodes, etc. This results in having a voltage at the starter but no large current flow.