Dash lights won't turn off 1992 lumina

if the coolant level is at the proper level and the thermostat is good then before you pull the heater core out you can try disconnecting the heater hoses and drain or blow out as much coolant out of the heater core then connect separate hoses to the spigots and fill the heater core with CLR and let it sit for an hour before draining then flush out with water and repeat if necessary this sometimes works and you won`t have to remove the heater core.

Theres a sensor in the middle of the dash by the front windshield that detects sunlight and triggers the automatic headlights. The main headlights and daytime running lights might be on a different circuit, in which case they daytime running lamps would turn off at night and the main headlights would turn on, indicating the main headlights arent working and the daytime running lamps are working as intended.

I would check all the fuses related to headlights, check the bulbs and check the switch, then last the light sensor on the dash.

anti theft deturent light flashing??with key on engine off??

that flasher is normally located in the top of the under dash fuse panel or hanging above the under dash fuse panel

check the dial by the light switch to make sure you don't have it turned down. It's a common mistake and embarrassing one as well. hitting it with a knee or rubbing it when trying to find the light switch in the night can jar it enough to turn it down....If that doesn't fix it, check your fuse box for a dead fuse to the instrument panel...

Have you tried turning up the dash light dimmer switch as bright as it can go? I will dim slightly but will still be alluminated

Turn the knob by the head light switch your tail lights work off the headlight switch not when the day time running lights are on only when you turn your headlights on

take it in for scrap at the junkyard...lol

that's the coolant level sensor. that coolant level light will stay on if it isn't installed.

try turning dimmer switch on the dash