1990 new yorker. fuse for the dash lights,radio and dome ligjts keeps blowing

I think there should be another fuse for the dash lights and radio and dome (or interior or courtesy it may be designated). Recheck all of those fuses under the dash, I believe one has blown out. This is when a wiring diagram comes in handy-you can see the fuse lay-out, and what circuits each one serves.

You have a direct short. Take the bulb out of dome light, inspect the socket. Try putting fuse back in while bulb is out. If the fuse blows again, Id say it's in the wiring from the fuse box to the the switch. If the dome light fuse also covers other electrical things, such as lighter, check the socket at all points. You mentioned that other fuses were replaced as well? Which ones, and why did they blow? Sometimes it could be moisture entering your fuse box, or condensation near the computer, but is sounds more like a short. Could be as minor a a bad ground wire, or a chafed wire. While you are putting the fuse back in, it will help to keep your eyes looking around the fuse box for sparks as soon as the fuse goes in. You should also listen for that electrical snap. If this doesn't help, I'd suggest taking head panel down and follow and inspect the wires from dome down to the switch. Then from switch [ which could also be the cause ] to fuse box. look for hot spots, arcs, and bare spots. I hope this helps you out. keep me informed

Does your interior dome light work,if it doesnt take the dome lamp assembly out and disconnect the wire harness from there, reinstall the fuse and recheck lights,The possible short is coming from 2 likely areas the dome light or the dimmer light,what you do to the dome light to trouble shoot the short you will also perform on the dimmmer switch

Pull the electrical connector to the visors out of the headliner and disconnect it from both visors, see if the short goes away.

You will have to trace the wiring. There is a short somewhere before it reaches the actual horn or light. Horns pull an extreme amount of amperage. The relay may be stuck or the wiring to the switch may be bad. My bet would be a shorted switch or relay.

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If they keep blowing there is a issue somewhere check for frayed wires or pinched wires.

You know whats connected to the fuse, now start systematically disconnect each component and each time you try the fuse same fault, reconnect, till you ge t to the component which you disconnect and do not blow the fuse, now you know it is in that component start tracing the wires/bulb connections. , have 10 spare fuses ready'

did u know that they make a harness for your car that plugs into your factory harness and then adapts to your aftermarket radio? for the lights, you have blown the interior light fuse, it may be the same fuse as the cigar lighter.Below is your radio wire colors and what they do.
1990 Toyota Corolla Car Stereo Radio Wiring Diagram.
Radio Constant 12V+ Wire: Blue/Yellow
Radio Switched 12V+ Wire: Gray
Radio Ground Wire: Brown
Radio Illumination Wire: Green
Radio Dimmer Wire: N/A
Radio Antenna Trigger Wire: N/A
Radio Amp Trigger Wire: N/A
Front Speakers Size: 4′
Front Speakers Location: Dash
Left Front Speaker Wire (+): Pink
Left Front Speaker Wire (-): Purple
Right Front Speaker Wire (+): Purple
Right Front Speaker Wire (-): Light Green
Rear Speakers Size: 4′
Rear Speakers Location: Rear Deck
Left Rear Speaker Wire (+): Black
Left Rear Speaker Wire (-): Yellow
Right Rear Speaker Wire (+): Red
Right Rear Speaker Wire (-): White
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Has the car ever been wrecked. Something maybe grounded somewhere.