[John Rogers]

You might want to try a remote starter button that are fairly cheap at auto parts stores? I have one and it hooks between the battery + terminal and the yellow lug on the starter connections. This bypasses the whole key, wire, relay board, etc so if the starter works okay with one of these then you can start eliminating instead of throwing things at it. On my race car I eventually wired a starter button in the engine compartment so I could start the car BEFORE I climbed in over the roll cage and all that stuff as being an old guy it was hard to get in/out.

If you do this, make sure the shifter is in neutral and the wheels are blocked!