Trying to save some $$$ aren't you?
You should have taken it to the dealer, while it may cost you more, they the proper diagnostic equipment and an encyclopedia of troubleshooting.......
The local dealership has seen this problem before and could not figure it out so they replaced the starter and when the owner went the next state over on a trip, same problem happened again to them. So, the dealership will just replace “something” and I will most likely be stuck with the same problem at some point.