12 volt accessory under the hood add a circuit issue
So I have been at this for a hour or 2 now and cannot figure out what I am doing wrong.
Basically, I added an accessory that needed 12 volt power. Since the accessory was under the hood, i wanted to find a 12 volt power source, that turned off and on with the key in the on or acc only position (basically so it was not on all the time). I figured I could just buy a add a circuit dealy for a few dollars, tag on to the (the slot number I cannot remember 56 maybe or 66) radio fuse (10 A I believe), and then I would have the 12 volt connection, and since the radio is killed every time the car stops, I assumed tagging onto that fuse slot would work. Well it did not. It still remains 12v constant.
Am I wrong in thinking that I can use an add to circuit in a fuse slot under the hood? I am getting pretty frustrated LOL.
Any help would be appreciated!