Ignition Switch

if its automatic trans, starter relay will have the yellow wire from your switch. That gets hot with switch in start position. the relay should also have a brown wire from neutral safety switch (automatic trans). If that doesn't provide a ground with trans in park or neutral, the relay wont function/close. You can short this brown wire to ground at the relay to prove relay is good and neutral safety switch is the problem.
If its manual trans the correct starter relay wont have a terminal for the neutral safety/brown wire. A lot of times the part stores would have only the automatic trans type relay in stock. Installer would need to add a ground jumper from neutral safety terminal to ground at the relay.