Headlights, dome lights, and radio shut off on my 1990 bronco!

I suspect a clogged fuel filter. Having lived on bumpy rural roads for years, I has to change the filter on my '86 Sunbird 3 or 4 times.

On the components, you might try a separate ground. See if that helps? Check the battery negative connections. I've seen this even on newer vehicle where instrument cluster or whatever would dim a little when you turn on headlamps. I think it's a ground issue? Just my opinion.
On any component that doesn't work, check voltage and ground, you could try a redundant ground.

check fuses/broken wire in light holder/bulbs

One of my driving lights went out after hitting a bump on a dirt road, how do I replace the bulb? It's not the headlight, it's the driving light or fog light.

Check your neutral safety switch. I had the same problem during a hard rain, hit a bump and everything went out.

check near the battery, the ground wire may have come loose or is not making good contact

Check battery cables. Clean and replace bolts that hold them on.

Get under the hood and start shaking the wire harnesses, while you have someone sit in the truck waiting for things to flicker on and off. Chances are good that you have a corroded connection that supplies quite a few gadgets. Also check the terminals coming off the battery, and any smaller wires attached to them. These frequently corrode faster than the larger wires. By the way, shaking the harnesses...is called, " THE WIGGLE TEST". Good luck. Chip

the connection to the light adjustment knob thats imbeded in your dash. the one that adjusts the intensity of your dash lights and such probably came loose or detached.

The Trac light comes on automatically, in conjuction with the Check Engine Light. You need your vehicle scanned for DTC codes.