Flywheel Ring

I have been getting an intermittent no start. The engine doesn't turn over and all i get is a click. The last time i brought it in i wrote up a list for them to check which includes: 1) Check for broken, loose or disconnected wires in the starting circuit. Inspect all wires and connectors at the battery, starter solenoid and igition switch (on the steering column) 2) Check starter motor and pinion jammed in flywheel ring gear. 3) Bad starter solenoid 4) Bad starter motor 5) Bad ignition switch. They replaced the remanufactured starter with another and i still get the intermittent no start. I went on the internet and searched for people who had a similar problem as i do with the same model and found the a bad interlock relay could cause the same no start, so i went to a junk yard and found a newer interlock relay and replaced it only to find it wasn't a bad relay. What should i do different this time when i bring it in to them? They are ASE and have trusted them for 15 yrs bring it