It's the "backup fuse" under the hood. 7.5 amps if I recall.

 

i see a 7.5 amp fuse called "backup, radio" under the hood. is that it?

 

That's the one. If you pull that, the car wont start. That's the one you pull to clear CEL codes from the computer. Pulling it also makes you lose all of your radio presets...

 

thanks. which size adapter goes into the spark plug holes? 18mm 16mm or 14mm?

 

Any ans all thos will work, the point is to make sur your car wont start whrn you try to crank it over. This can be done by disconnecting the fuel pump fuse, removing the distributor cap or removing ALL the spark plugs. I personally prefer to disconnect the distributor from the coil but thats on an aurcooled vw where to coil is external unlike the civic. The important part is to either stop the fuel or stop the spark so you can safely crank it with no start risk