I have a 2000 Honda Civic that won't turn over sometimes. When I turn the key on, the dash lights operate but the starter never engages. This happens randomly and it doesn't seem to matter what the temperature is. Turning the key off and back on again usually causes the car to start.

The battery is okay
The ignition switch is okay, it's been replaced.
The starter is okay, it's been replaced.

This leaves me to think it is a relay or the shifter switch acting up.

What are the relays I should check and where are they located? I'm guessing the main relay but I can't find anything that tells where it is located and I'm guessing there is a starter relay but again, I can't find it.

 

Manual has a starter interlock relay which I think is still near the clutch pedal since it is connected to the pedal switch to prevent starting unless the clutch is held down. Automatic has a switch on the shifter but I think there is no relay, the circuit just goes directly from the key through the switch to the starter.

Usually this problem is bad connections at the battery or a problem in the starter itself. You can bypass all the switches and relays in the car by jumping the starter with a wire from the small terminal on the starter to the battery. Make sure car is in park or neutral because the engine will turn if the starter works.