1999 Civic EX. Was going down the road and I hit a huge bump. Occasionally it would blow the always hot 7.5 backup fuse, but I would replace it and the radio would turn right back on. Now Ive replaced both the fuse under the dash and under the hood and the radio won’t turn on. Light on it is illuminated which I presume means it has power. It’s a kenwood if that matters. Where should i start?

 

Remove the radio and test/check the fuse that is on the actual headunit as well. Most aftermarket headunits will have a fuse on them.

 

That constant on 12v from the fuse under the hood called backup is usually wired to the yellow wire. Then the 12v switched on from interior fuse box is usually going to the red. Then the previously mentioned fuse on the back of the hu usually a 10amp. If you look at the plug from a civic the wires are all extremely small almost like dental floss. But it's fine because the stock radio puts out something like 2-3 watts per channel. Now your at 20-25 watts rms per channel. Even the Accord with only a slightly more powerful radio has larger gauge wire for red/yellow/black. I say keep the switched 12v, and add new positive and neg for the hu. You don't need to go crazy and run an amp installation kit, but something like 16 or 20 gauge would be a nice improvement. I found some installbay brand red wire I think it was 16 gauge. It has a thicker insulation on it that that generic red power wire found at the autoparts store. Also there's more twists per inch and finer strands of copper. This is what you want because electrical noise is the enemy. So it goes from the back of the hu to the fuse box under the hood. I had to cut the fuse box lid a little and there's a 30 amp fuse installed. There's a nice spot to ground to just below the hu near the cigarette lighter. I put black tape over that wire but you could buy some black wire if you really wanted.