Lights will not come on after changing radio.

First of all, what do you mean "like wires"? If you just matched up colors, there is no rhyme or reason to the colors the harness supplier uses. You have to go according to function. Electrical tape is a very bad idea. It IS going to unravel into a gooey mess, and if you didn't solder the wires, one could have gotten snagged when you pushed the radio in and pulled apart and shorted to ground. The only acceptable way to splice in a different harness is to twist the wires, solder them, then seal them with heat-shrink tubing. I don't mean twist like you're installing a wire nut. I mean twist like they do with those goofy donuts that they grab by the sides and give a twist to. Essentially you're bringing the bared ends of the two wires up to each other, overlapping just the bared copper, and twisting them around each other. After they're soldered, flatten any points of copper wire that are sticking up so they don't work their way through the heat-shrink tubing later.

The place to start now is by removing and unplugging the new radio, then diagnosing the lighting problems. There are two lighting wires in the radio harness that went to the original radio. One is tied to the running lights and tells the display to dim when the head lights are turned on. The other one comes from the dash lights and tells the display how much to dim. If those were wired to something or touched anything metal, a fuse would likely be blown. Check inside and under the hood for two fuse boxes. I don't know how that could affect just one head light. Any chance it just decided to burn out now?