I have a 84 Chevy s/b and the old cigarette lighter was shorting out anytime I plugged anything into it to use it. I got a new one and was changing it out, when I was tightening it into the holder it sparked. Checked the fuse and it was blown so changed it. With the new fuse there was still no power to the cigarette lighter and now my horn and switch to change fuel tanks does not work either. I checked the fuse box and where the fuse was that I changed it looks blackened. I got a test light to see if there was power at the box and the right side has power and the left side does not. So what I am wondering is if anyone knows if there is another place to look for another problem or is it possiable the wire at the back of the fuse box has come off?

your fuse is blown again. You gotta find out why it's popping them.

I checked the fuse box and where the fuse was that I changed it looks blackened. I got a test light to see if there was power at the box and the right side has power and the left side does not.

A fuse block or fuse location only has power to one side. The fuse is what completes the circuit. When it pops you have a dead short on the non power side somewhere (dead short + bare wire or power shorting to a ground) Check the full length of your wire to the ciggy lighter. Chances are it is cracked and shorting out. Splice and/or replace. And never, never use electrical tape to cover a wire. Connectors are only a few pennies apiece. Use the proper connectors and a good crimp tool. If you find any tape wrapped connections under the dash, replace them. One more thing to look at is the connector at the ciggy lighter itself. The one on the wire that pushes onto the threaded portion of the lighter.....it is not pushing on too far so as to short out on the case is it. If you look closely the case is isolated from the threaded stud. What makes the lighter work is actually shorting the ground to the positive by way of the metal coil on the lighter itself. A fuse will pop but the metallic wire will heat up due to it construction.

Kevin