Yet Another car won't start problem

Another car won’t start problem w/ my 91 teg RS
hear click sound and does not start.
if i continue to keep turning the key for few secs the car starts fine.
car is manual w/ 108k mi
msd blaster ignition

  • where does the starter relay located?

  • starter already replaced so it might be fuel relay or starter relay?

  • how to test if it’s fuel relay or starter relay other than replacing them?

sorry for the dumb questions but i’m not quite mechanical inclined…but i wish to learn to do maintainence on my car.

Thanks

I had that problem and all it took was a good cleaning of the starter’s electrical connection surfaces.