My dashboard has come unattached from the car and my lights dont work half the time

I would suspect a blown fuse that may be under the hood or a fusible link.

Your half way there. All you need is a wiring diagram to trace the wire from the ignition to that fuse. Most likely it is one wire from the ignition, then it splices to the different fuses. In my experience the splice fails(corrosion), Some times you loose one area, some times all. Depends on which side of the splice is corroded the most. Splices are hard to find. Even harness diagrams can be as much as 2 feet off. I usually find the color code of the wire and run a new wire. In your case, it would be from the ignition switch to the fuse panel.

Honestly dont know but I would be straight to an auto electrician. Sounds like parrallel wiring may have worn (from rubbing) and is playing havoc by activating neighbouring wires or the fuse box has a faulty circuits.

If all your fuses are good, start looking at your ignition switch. It's the one thing all those circuits have in common.

Have someone check fuse under dashboard. Some dashboards have lights wired in series. If one light goes out, they all go out.

Please clarify:
Half of your dash lights are not working?
All your dash lights are dim?
IF all are dim, to the right of the headlight switch, there is a dimmer 'wheel' rolling up = max illumination, until it clicks to turn on enterer dome light.

mine was both a bad wiper switch and wiper motor.
when my dash lights acted up, a new HL switch sorted me out fine.

If the car cranks well then might have a loose connection to dashboard or a bad ground. I don't think this is much help but might be a starting place.

DASH LIGHTS ON 850 VOLVOS SOMETIMES THEY DONT MAKE A GOOD CONTCACT I REPLACED MY ISTRUMENT CLUSTER AND HAD TO TKE IT OUT 4 TIMES AND PUT ELECTRICAL GREASE ON BULBS AND CHECK THE DIMMER SWITCH IS ALL THE WAY TO THE RIGHT OR THE HEADLIGHT SWITCH PLUG

check the fuse first if not that, than replace the windshield whiper motor under plastic panel between the hinges of the hood.