I have a 04 Rx-8 with about 107k miles on the stock motor and manual transmission and recently ran into some starting issues. When I go to crank the car I push the clutch in all the way to the floor and turn the key. I get no clicks or sounds from the starter attempting to turn the engine over as well my center console and all 12 volt outlets loose power while turning the key.
Troubleshooting I have already preformed:
-Checked the battery and terminals as well as changed the negative terminal out-(even disconnected the battery and done the resets for everything)
-Checked all fuses and relays (ill expand on this further down because there is something interesting to be said here)
-Attempted to bypass the clutch position sensor to see if that was failing
-Checked grounds
-Checked under the dash for any loose connections
-Only thing I have been unable to check is the starter because I just got back home after getting the thing towed back.

So to expand on the fuses and relays I found that when I mess with the EGI and ETV relays the car will start up, but correlation doesn't mean causation and the more I finagle with them the less it seams to work.
Im at my wits end now because the car still preforms all of the normal start up sounds and you can hear the relays do their thing but the car just wont turn over. Any thoughts or Input would be greatly appreciated.

 

Update - So I took the starter and battery to get checked both are fine, going to check the master fuse contact again, also there are two plungers near the clutch and if I remember correctly some people have had issues with the one closes to the firewall? Should I jump straight for that?

 

Got the battery tested and starter tested still good. I even sanded down where the starter makes contact. Going to order new relays soon. Still loosing all power when I turn the key.

 

Clutch safety switch would be one place to check, as you noted earlier. It's on the clutch pedal.

 

If relay futzing make it work... Even for a short time, I would swap the now 14 year old relays for new ones if it were my car.