Interior stereo light

There are two fuses, all in the fuse box. One for the radio itself (which probably is the one that went out) and another one for the night illumination, which works together with the dash lights / dimmer.
The one for the radio is on the passenger side fuse box. Look in the manual for the right location, I think it is #12 or 13

I would check the fuses for the radio. One should be in the engine compartment distribution box and there should be another fuse in the interior fuse box. If these fuses are intact and you have a multimeter, I would check the presence of at least 2 pins with + 12 Volt on the radio connector. The pin out diagram can be seen if you do a search for the 2001 Taurus. Good luck, hope this helps.

take stereo out check your wiring and also check your fuses

check all the fuses in your fuse relay box in your engine bay for a blown fuse also check inside the car sometimes theres another fuse box stashed there.

Hello,

was the radio and interior light working before you removed the fuse for the horn? In the process of removing the fuse for the horn, you must have mistakenly tempered with the fuse for the radio and interior light.

So I would suggest you go back to the fuse box and deep them in properly because the interior and radio fuse might not be contacting properly.

I hope this makes sense to you.

Good luck.

Are you sure no fuse was blown? there are more than 1 fuse box (in engine and under dashboard).

you possibly have a broken fuse somewhere, whether it is the fuse relay between the stereo and the fuse box or if it is the fuse broken in the fuse box itself. check the fuses fisrt.

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
-->

check these fuses radio/interior lights
Radio backup (if applicable)
Ignition

Most factory stereos are wired to the dash dimmer switch. Usually if the dash lights go out after an after market stereo installation, it is because the wire that originally went to the factory stereo is not used for after market stereos. Double check the fuses and ensure the wire that controlled the lights on the factory stereo is not grounding out on something.