the fuse box is two parts. The inner (maybe brown) part has 4 clips on the outside edges. Unlock them and the inner part of the box will pick up allowing access to the 120 amp fuse. Need 8mm socket.

 

I have an 05 Rx-8 manual. I parked the car about 6 months ago due to life getting in the way I was unable to use the car. The car battery obviously died so I tried to replace it, however, as soon as I connected the new battery the horn went off and the lights turned on... I removed the horn fuse to try and see what the issue was but lights in the dash or radio will not turn on when the battery is connected. I checked the 120v fuse and its fine. I tried to unlock the trunk as some people have recommended but no luck. Any help would be appreciated the car was sitting outside uncovered during its hibernation.