2002 Saturn L100 No Cruise control, audio after panic horn

There could be a fuse or relay issue since multiple systems became inoperative simultaneously. I'd suspect that when the alarm went off, someone targeted and disabled the horn system so that it wasn't honking inside the repair facility. Both the horn switch and cruise control switch are located in the steering wheel and therefore they share common components and circuitry. Try checking under-hood fuses #7 (7.5A), #13 (20A), #15 (40A) and #20 (40A), as well as under-dash fuses #7 (7.5A) and 21 (7.5A). If all these fuses are OK, much deeper diagnosis will need to be performed. One somewhat common failure item is the spiral cable (also called a clock spring) that transfers power to the steering wheel (while allowing it to turn). That part can be seen within the steering angle replacement procedure shown here: https://www.yourmechanic.com/article/how-to-replace-a-steering-angle-sensor-by-marvin-sunderland

Question edited for clarity, 'fuse', unless you light it 'fuze'.Question moved to sub category.

If the radio has an inline fuse, it will be within 82 of the plug at the rear. They are built into the harness. Unlikely because there are three fuses covering audio.

https://fuse-box.info/isuzu/isuzu-trooper-1992-2002-fuses-and-relays

C11 10 (AUDIO[ACC]) MIRROR Audio, Door mirror, Door mirror control SW, Door mirror folding SW, Digital clock, Speaker C12 20 CIGARETTE Cigarette lighter C13 10 ANTI THEFT Anti-theft controller C14 15 STOP A/T CONT Stoplight SW (w/o cruise control), Brake SW (w/cruise control), Rear wheel anti-lock brake controller, Stoplight, Transmission control module, Electronic brake control module, Trailer harness connector, Cruise control unit, A/T shift lock control unit, Lockup off relay C15 20 AUDIO[BJ] Horn, Horn relay, Horn SW, Hazard warning light SW, Flasher unit, Anti-theft horn, Hazard warning light, Audio C15 20 TELEPHONE Telephone C16 10 CLOCK[B] ROOM Digital clock, Audio, Dome light, Map light, Luggage room light, Courtesy light, Door SW (Front, rear, tail gate), Antenna, Anti-theft controller, Key remind SW, Seat belt, Key & light remind buzzer

Fuse #19 (15 amp) controls the cruise control. It also powers the horn so check your horn. If it works then check the cruise controls ground. If the fuse is good BUT the horn still doesn't work, then check the horn relay, as it also powers the cruise control. Check all wires/connections going to these parts also.

You have a fuse / relay box under your hood. My 2002 L100 special edition, 4 cylinder, is located near the battery. You have a relay and a fuse in series. A fuel pump operations check, section 4-3 of the Haynes Saturn L-series 2000 to 2004 manual, you can hear a soft whirring sound for 1 to 2 seconds when you turn the ignition to the ON position. I can confirm mine makes this sound when I do this. Good luck with the fix.

Note, I had a crack in my fuel pump, but I took it to an ex-Saturn dealer 4 or 5 years ago because I did not want to mess with it at the time. They had the part and fixed it in 4 hours, but it also cost me $1000 to replace the fuel pump and install a new fuel filter.

there is two sets of fuses on this car i think. The centre console lights are on fuses inside the car under the dash, is your interior light not working either?

you may have sett off the panic button on your key chain that caused the car to go into panic mode for the computer. i have had this happen with my old 2000 malibu one suggestion i would say is to try pressing the panic button a few times to see if that is engaging or may disengage the system.
how ever thats if it is related to the panic mode of your car.
other solutions is buy a new horn or horn relay
you may have a short in the horn that could also be making it go off continually. if you are still having trouble see a chevy dealer shop and talk with them about your issue.

More than likely you just need a brake switch, just make sure you ask for the cruise deactivation brake switch.

check the fuses but there should also be a relay for these "toys" located either in the fuse box under the dash or in the fuse box in the engine compartment often located near the battery.

There is a push relay under the steering padding. Could be stuck. If the fuse is good to the cruise control, the module is usually bad.

First this only applies if your cruise buttons are on your steering wheel. If so look into a possible problem with the clockspring mounted in your steering column! Good Luck!