I have 2001 Honda Civic and just replaced the battery. Car now will not start, no clicking sound when turning the key in the ignition. I checked the battery and it outputs 12V. I also noticed that the headlights don't turn-on, radio doesn't work, and interior lights don't turn on. I'm pretty certain the battery connections are tight. I checked the battery fuse and its not opened.

Any suggestions on what to check?

 

when its a power issue u jus have to go down line check and fuse box next relays jus go down the line

 

Usually this is because of a bad connection at the battery. Redo the connections, take the terminal off and scrape to make sure the inside surface that makes contact is clean. Loosen the nut and spread the terminal open so it goes all the way down on the post and then tighten.

If that doesn't work you'll need to make some measurements to see where the voltage is being lost. For example measuring from the frame ground and engine ground to battery (-) will check the ground system. It should be approximately zero volts. If you have voltage then measure across smaller parts of the chain to see which connection is bad. During this test turn the light switch on so there is a load on the circuit.

 

issue resolved. Doubled check the main fuse to the battery and it was blown.